Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

76 files changed, 6372 insertions, 0 deletions

diff --git a/devtools/client/jsonview/.eslintrc.js b/devtools/client/jsonview/.eslintrc.js
new file mode 100644
index 0000000000..cd16102c98
--- /dev/null
+++ b/devtools/client/jsonview/.eslintrc.js
@@ -0,0 +1,15 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+module.exports = {
+  globals: {
+    define: true,
+    document: true,
+    window: true,
+    CustomEvent: true,
+    JSONView: true,
+  },
+};
diff --git a/devtools/client/jsonview/Converter.sys.mjs b/devtools/client/jsonview/Converter.sys.mjs
new file mode 100644
index 0000000000..560f82440a
--- /dev/null
+++ b/devtools/client/jsonview/Converter.sys.mjs
@@ -0,0 +1,17 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * Create instances of the JSON view converter.
+ */
+export function Converter() {
+  const { require } = ChromeUtils.importESModule(
+    "resource://devtools/shared/loader/Loader.sys.mjs"
+  );
+  const {
+    JsonViewService,
+  } = require("resource://devtools/client/jsonview/converter-child.js");
+
+  return JsonViewService.createInstance();
+}
diff --git a/devtools/client/jsonview/Sniffer.sys.mjs b/devtools/client/jsonview/Sniffer.sys.mjs
new file mode 100644
index 0000000000..d585ce8ab2
--- /dev/null
+++ b/devtools/client/jsonview/Sniffer.sys.mjs
@@ -0,0 +1,64 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";
+
+const gPrefs = {};
+
+XPCOMUtils.defineLazyPreferenceGetter(
+  gPrefs,
+  "gEnabled",
+  "devtools.jsonview.enabled"
+);
+
+const JSON_VIEW_MIME_TYPE = "application/vnd.mozilla.json.view";
+
+function getContentDisposition(channel) {
+  try {
+    return channel.contentDisposition;
+  } catch (e) {
+    // Channel doesn't support content dispositions
+    return null;
+  }
+}
+
+/**
+ * This component represents a sniffer (implements nsIContentSniffer
+ * interface) responsible for changing top level 'application/json'
+ * document types to: 'application/vnd.mozilla.json.view'.
+ *
+ * This internal type is consequently rendered by JSON View component
+ * that represents the JSON through a viewer interface.
+ *
+ * This is done in the .js file rather than a .jsm to avoid creating
+ * a compartment at startup when no JSON is being viewed.
+ */
+export class Sniffer {
+  getMIMETypeFromContent(request, data, length) {
+    if (request instanceof Ci.nsIChannel) {
+      // JSON View is enabled only for top level loads only.
+      if (
+        gPrefs.gEnabled &&
+        request.loadInfo?.isTopLevelLoad &&
+        request.loadFlags & Ci.nsIChannel.LOAD_DOCUMENT_URI &&
+        getContentDisposition(request) != Ci.nsIChannel.DISPOSITION_ATTACHMENT
+      ) {
+        // Check the response content type and if it's a valid type
+        // such as application/json or application/manifest+json
+        // change it to new internal type consumed by JSON View.
+        if (/^application\/(?:.+\+)?json$/.test(request.contentType)) {
+          return JSON_VIEW_MIME_TYPE;
+        }
+      } else if (request.contentType === JSON_VIEW_MIME_TYPE) {
+        return "application/json";
+      }
+    }
+
+    return "";
+  }
+}
+
+Sniffer.prototype.QueryInterface = ChromeUtils.generateQI([
+  "nsIContentSniffer",
+]);
diff --git a/devtools/client/jsonview/components.conf b/devtools/client/jsonview/components.conf
new file mode 100644
index 0000000000..e4fc8ba458
--- /dev/null
+++ b/devtools/client/jsonview/components.conf
@@ -0,0 +1,26 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+JSON_VIEW_MIME_TYPE = "application/vnd.mozilla.json.view"
+
+Classes = [
+    {
+        'cid': '{4148c488-dca1-49fc-a621-2a0097a62422}',
+        'contract_ids': ['@mozilla.org/devtools/jsonview-sniffer;1'],
+        'esModule': 'resource://devtools/client/jsonview/Sniffer.sys.mjs',
+        'constructor': 'Sniffer',
+        'categories': {
+            'net-content-sniffers': 'JSONView',
+            'net-and-orb-content-sniffers': 'JSONView',
+         },
+    },
+    {
+        'cid': '{d8c9acee-dec5-11e4-8c75-1681e6b88ec1}',
+        'contract_ids': ['@mozilla.org/streamconv;1?from=%s&to=*/*' % JSON_VIEW_MIME_TYPE],
+        'esModule': 'resource://devtools/client/jsonview/Converter.sys.mjs',
+        'constructor': 'Converter',
+    },
+]
diff --git a/devtools/client/jsonview/components/Headers.js b/devtools/client/jsonview/components/Headers.js
new file mode 100644
index 0000000000..7477627328
--- /dev/null
+++ b/devtools/client/jsonview/components/Headers.js
@@ -0,0 +1,118 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+define(function (require, exports, module) {
+  const {
+    createFactory,
+    Component,
+  } = require("devtools/client/shared/vendor/react");
+  const PropTypes = require("devtools/client/shared/vendor/react-prop-types");
+  const dom = require("devtools/client/shared/vendor/react-dom-factories");
+
+  const { div, span, table, tbody, tr, td } = dom;
+
+  /**
+   * This template is responsible for rendering basic layout
+   * of the 'Headers' panel. It displays HTTP headers groups such as
+   * received or response headers.
+   */
+  class Headers extends Component {
+    static get propTypes() {
+      return {
+        data: PropTypes.object,
+      };
+    }
+
+    constructor(props) {
+      super(props);
+      this.state = {};
+    }
+
+    render() {
+      const data = this.props.data;
+
+      return div(
+        { className: "netInfoHeadersTable" },
+        div(
+          { className: "netHeadersGroup" },
+          div(
+            { className: "netInfoHeadersGroup" },
+            JSONView.Locale["jsonViewer.responseHeaders"]
+          ),
+          table(
+            { cellPadding: 0, cellSpacing: 0 },
+            HeaderListFactory({ headers: data.response })
+          )
+        ),
+        div(
+          { className: "netHeadersGroup" },
+          div(
+            { className: "netInfoHeadersGroup" },
+            JSONView.Locale["jsonViewer.requestHeaders"]
+          ),
+          table(
+            { cellPadding: 0, cellSpacing: 0 },
+            HeaderListFactory({ headers: data.request })
+          )
+        )
+      );
+    }
+  }
+
+  /**
+   * This template renders headers list,
+   * name + value pairs.
+   */
+  class HeaderList extends Component {
+    static get propTypes() {
+      return {
+        headers: PropTypes.arrayOf(
+          PropTypes.shape({
+            name: PropTypes.string,
+            value: PropTypes.string,
+          })
+        ),
+      };
+    }
+
+    constructor(props) {
+      super(props);
+
+      this.state = {
+        headers: [],
+      };
+    }
+
+    render() {
+      const headers = this.props.headers;
+
+      headers.sort(function (a, b) {
+        return a.name > b.name ? 1 : -1;
+      });
+
+      const rows = [];
+      headers.forEach(header => {
+        rows.push(
+          tr(
+            { key: header.name },
+            td(
+              { className: "netInfoParamName" },
+              span({ title: header.name }, header.name)
+            ),
+            td({ className: "netInfoParamValue" }, header.value)
+          )
+        );
+      });
+
+      return tbody({}, rows);
+    }
+  }
+
+  const HeaderListFactory = createFactory(HeaderList);
+
+  // Exports from this module
+  exports.Headers = Headers;
+});
diff --git a/devtools/client/jsonview/components/HeadersPanel.js b/devtools/client/jsonview/components/HeadersPanel.js
new file mode 100644
index 0000000000..0e9e17190e
--- /dev/null
+++ b/devtools/client/jsonview/components/HeadersPanel.js
@@ -0,0 +1,56 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+define(function (require, exports, module) {
+  const { Component } = require("devtools/client/shared/vendor/react");
+  const PropTypes = require("devtools/client/shared/vendor/react-prop-types");
+  const dom = require("devtools/client/shared/vendor/react-dom-factories");
+
+  const { createFactories } = require("devtools/client/shared/react-utils");
+
+  const { Headers } = createFactories(
+    require("devtools/client/jsonview/components/Headers")
+  );
+  const { HeadersToolbar } = createFactories(
+    require("devtools/client/jsonview/components/HeadersToolbar")
+  );
+
+  const { div } = dom;
+
+  /**
+   * This template represents the 'Headers' panel
+   * s responsible for rendering its content.
+   */
+  class HeadersPanel extends Component {
+    static get propTypes() {
+      return {
+        actions: PropTypes.object,
+        data: PropTypes.object,
+      };
+    }
+
+    constructor(props) {
+      super(props);
+
+      this.state = {
+        data: {},
+      };
+    }
+
+    render() {
+      const data = this.props.data;
+
+      return div(
+        { className: "headersPanelBox tab-panel-inner" },
+        HeadersToolbar({ actions: this.props.actions }),
+        div({ className: "panelContent" }, Headers({ data }))
+      );
+    }
+  }
+
+  // Exports from this module
+  exports.HeadersPanel = HeadersPanel;
+});
diff --git a/devtools/client/jsonview/components/HeadersToolbar.js b/devtools/client/jsonview/components/HeadersToolbar.js
new file mode 100644
index 0000000000..f9122c3a31
--- /dev/null
+++ b/devtools/client/jsonview/components/HeadersToolbar.js
@@ -0,0 +1,51 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+define(function (require, exports, module) {
+  const { Component } = require("devtools/client/shared/vendor/react");
+  const PropTypes = require("devtools/client/shared/vendor/react-prop-types");
+  const { createFactories } = require("devtools/client/shared/react-utils");
+
+  const { Toolbar, ToolbarButton } = createFactories(
+    require("devtools/client/jsonview/components/reps/Toolbar")
+  );
+
+  /**
+   * This template is responsible for rendering a toolbar
+   * within the 'Headers' panel.
+   */
+  class HeadersToolbar extends Component {
+    static get propTypes() {
+      return {
+        actions: PropTypes.object,
+      };
+    }
+
+    constructor(props) {
+      super(props);
+      this.onCopy = this.onCopy.bind(this);
+    }
+
+    // Commands
+
+    onCopy(event) {
+      this.props.actions.onCopyHeaders();
+    }
+
+    render() {
+      return Toolbar(
+        {},
+        ToolbarButton(
+          { className: "btn copy", onClick: this.onCopy },
+          JSONView.Locale["jsonViewer.Copy"]
+        )
+      );
+    }
+  }
+
+  // Exports from this module
+  exports.HeadersToolbar = HeadersToolbar;
+});
diff --git a/devtools/client/jsonview/components/JsonPanel.js b/devtools/client/jsonview/components/JsonPanel.js
new file mode 100644
index 0000000000..f569aad4c6
--- /dev/null
+++ b/devtools/client/jsonview/components/JsonPanel.js
@@ -0,0 +1,163 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+define(function (require, exports, module) {
+  const {
+    createFactory,
+    Component,
+  } = require("devtools/client/shared/vendor/react");
+  const dom = require("devtools/client/shared/vendor/react-dom-factories");
+  const PropTypes = require("devtools/client/shared/vendor/react-prop-types");
+  const { createFactories } = require("devtools/client/shared/react-utils");
+
+  const TreeView = createFactory(
+    require("devtools/client/shared/components/tree/TreeView")
+  );
+  const { JsonToolbar } = createFactories(
+    require("devtools/client/jsonview/components/JsonToolbar")
+  );
+
+  const {
+    MODE,
+  } = require("devtools/client/shared/components/reps/reps/constants");
+  const { Rep } = require("devtools/client/shared/components/reps/reps/rep");
+
+  const { div } = dom;
+
+  function isObject(value) {
+    return Object(value) === value;
+  }
+
+  /**
+   * This template represents the 'JSON' panel. The panel is
+   * responsible for rendering an expandable tree that allows simple
+   * inspection of JSON structure.
+   */
+  class JsonPanel extends Component {
+    static get propTypes() {
+      return {
+        data: PropTypes.oneOfType([
+          PropTypes.string,
+          PropTypes.array,
+          PropTypes.object,
+          PropTypes.bool,
+          PropTypes.number,
+        ]),
+        dataSize: PropTypes.number,
+        expandedNodes: PropTypes.instanceOf(Set),
+        searchFilter: PropTypes.string,
+        actions: PropTypes.object,
+      };
+    }
+
+    constructor(props) {
+      super(props);
+      this.state = {};
+      this.onKeyPress = this.onKeyPress.bind(this);
+      this.onFilter = this.onFilter.bind(this);
+      this.renderValue = this.renderValue.bind(this);
+      this.renderTree = this.renderTree.bind(this);
+    }
+
+    componentDidMount() {
+      document.addEventListener("keypress", this.onKeyPress, true);
+      document.getElementById("json-scrolling-panel").focus();
+    }
+
+    componentWillUnmount() {
+      document.removeEventListener("keypress", this.onKeyPress, true);
+    }
+
+    onKeyPress(e) {
+      // XXX shortcut for focusing the Filter field (see Bug 1178771).
+    }
+
+    onFilter(object) {
+      if (!this.props.searchFilter) {
+        return true;
+      }
+
+      const json = object.name + JSON.stringify(object.value);
+      return json.toLowerCase().includes(this.props.searchFilter.toLowerCase());
+    }
+
+    renderValue(props) {
+      const member = props.member;
+
+      // Hide object summary when non-empty object is expanded (bug 1244912).
+      if (isObject(member.value) && member.hasChildren && member.open) {
+        return null;
+      }
+
+      // Render the value (summary) using Reps library.
+      return Rep(
+        Object.assign({}, props, {
+          cropLimit: 50,
+          noGrip: true,
+          isInContentPage: true,
+        })
+      );
+    }
+
+    renderTree() {
+      // Append custom column for displaying values. This column
+      // Take all available horizontal space.
+      const columns = [
+        {
+          id: "value",
+          width: "100%",
+        },
+      ];
+
+      // Render tree component.
+      return TreeView({
+        object: this.props.data,
+        mode: MODE.TINY,
+        onFilter: this.onFilter,
+        columns,
+        renderValue: this.renderValue,
+        expandedNodes: this.props.expandedNodes,
+      });
+    }
+
+    render() {
+      let content;
+      const data = this.props.data;
+
+      if (!isObject(data)) {
+        content = div(
+          { className: "jsonPrimitiveValue" },
+          Rep({
+            object: data,
+          })
+        );
+      } else if (data instanceof Error) {
+        content = div({ className: "jsonParseError" }, data + "");
+      } else {
+        content = this.renderTree();
+      }
+
+      return div(
+        { className: "jsonPanelBox tab-panel-inner" },
+        JsonToolbar({
+          actions: this.props.actions,
+          dataSize: this.props.dataSize,
+        }),
+        div(
+          {
+            className: "panelContent",
+            id: "json-scrolling-panel",
+            tabIndex: 0,
+          },
+          content
+        )
+      );
+    }
+  }
+
+  // Exports from this module
+  exports.JsonPanel = JsonPanel;
+});
diff --git a/devtools/client/jsonview/components/JsonToolbar.js b/devtools/client/jsonview/components/JsonToolbar.js
new file mode 100644
index 0000000000..34e6ed285b
--- /dev/null
+++ b/devtools/client/jsonview/components/JsonToolbar.js
@@ -0,0 +1,92 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+define(function (require, exports, module) {
+  const { Component } = require("devtools/client/shared/vendor/react");
+  const PropTypes = require("devtools/client/shared/vendor/react-prop-types");
+
+  const { createFactories } = require("devtools/client/shared/react-utils");
+  const { div } = require("devtools/client/shared/vendor/react-dom-factories");
+
+  const { SearchBox } = createFactories(
+    require("devtools/client/jsonview/components/SearchBox")
+  );
+  const { Toolbar, ToolbarButton } = createFactories(
+    require("devtools/client/jsonview/components/reps/Toolbar")
+  );
+
+  /* 100kB file */
+  const EXPAND_THRESHOLD = 100 * 1024;
+
+  /**
+   * This template represents a toolbar within the 'JSON' panel.
+   */
+  class JsonToolbar extends Component {
+    static get propTypes() {
+      return {
+        actions: PropTypes.object,
+        dataSize: PropTypes.number,
+      };
+    }
+
+    constructor(props) {
+      super(props);
+      this.onSave = this.onSave.bind(this);
+      this.onCopy = this.onCopy.bind(this);
+      this.onCollapse = this.onCollapse.bind(this);
+      this.onExpand = this.onExpand.bind(this);
+    }
+
+    // Commands
+
+    onSave(event) {
+      this.props.actions.onSaveJson();
+    }
+
+    onCopy(event) {
+      this.props.actions.onCopyJson();
+    }
+
+    onCollapse(event) {
+      this.props.actions.onCollapse();
+    }
+
+    onExpand(event) {
+      this.props.actions.onExpand();
+    }
+
+    render() {
+      return Toolbar(
+        {},
+        ToolbarButton(
+          { className: "btn save", onClick: this.onSave },
+          JSONView.Locale["jsonViewer.Save"]
+        ),
+        ToolbarButton(
+          { className: "btn copy", onClick: this.onCopy },
+          JSONView.Locale["jsonViewer.Copy"]
+        ),
+        ToolbarButton(
+          { className: "btn collapse", onClick: this.onCollapse },
+          JSONView.Locale["jsonViewer.CollapseAll"]
+        ),
+        ToolbarButton(
+          { className: "btn expand", onClick: this.onExpand },
+          this.props.dataSize > EXPAND_THRESHOLD
+            ? JSONView.Locale["jsonViewer.ExpandAllSlow"]
+            : JSONView.Locale["jsonViewer.ExpandAll"]
+        ),
+        div({ className: "devtools-separator" }),
+        SearchBox({
+          actions: this.props.actions,
+        })
+      );
+    }
+  }
+
+  // Exports from this module
+  exports.JsonToolbar = JsonToolbar;
+});
diff --git a/devtools/client/jsonview/components/LiveText.js b/devtools/client/jsonview/components/LiveText.js
new file mode 100644
index 0000000000..d90c099340
--- /dev/null
+++ b/devtools/client/jsonview/components/LiveText.js
@@ -0,0 +1,43 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+define(function (require, exports, module) {
+  const { Component } = require("devtools/client/shared/vendor/react");
+  const PropTypes = require("devtools/client/shared/vendor/react-prop-types");
+  const { findDOMNode } = require("devtools/client/shared/vendor/react-dom");
+  const { pre } = require("devtools/client/shared/vendor/react-dom-factories");
+
+  /**
+   * This object represents a live DOM text node in a <pre>.
+   */
+  class LiveText extends Component {
+    static get propTypes() {
+      return {
+        data: PropTypes.instanceOf(Text),
+      };
+    }
+
+    componentDidMount() {
+      this.componentDidUpdate();
+    }
+
+    componentDidUpdate() {
+      const el = findDOMNode(this);
+      if (el.firstChild === this.props.data) {
+        return;
+      }
+      el.textContent = "";
+      el.append(this.props.data);
+    }
+
+    render() {
+      return pre({ className: "data" });
+    }
+  }
+
+  // Exports from this module
+  exports.LiveText = LiveText;
+});
diff --git a/devtools/client/jsonview/components/MainTabbedArea.js b/devtools/client/jsonview/components/MainTabbedArea.js
new file mode 100644
index 0000000000..f340cbd89e
--- /dev/null
+++ b/devtools/client/jsonview/components/MainTabbedArea.js
@@ -0,0 +1,120 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+define(function (require, exports, module) {
+  const { Component } = require("devtools/client/shared/vendor/react");
+  const PropTypes = require("devtools/client/shared/vendor/react-prop-types");
+  const { createFactories } = require("devtools/client/shared/react-utils");
+  const { JsonPanel } = createFactories(
+    require("devtools/client/jsonview/components/JsonPanel")
+  );
+  const { TextPanel } = createFactories(
+    require("devtools/client/jsonview/components/TextPanel")
+  );
+  const { HeadersPanel } = createFactories(
+    require("devtools/client/jsonview/components/HeadersPanel")
+  );
+  const { Tabs, TabPanel } = createFactories(
+    require("devtools/client/shared/components/tabs/Tabs")
+  );
+
+  /**
+   * This object represents the root application template
+   * responsible for rendering the basic tab layout.
+   */
+  class MainTabbedArea extends Component {
+    static get propTypes() {
+      return {
+        jsonText: PropTypes.instanceOf(Text),
+        activeTab: PropTypes.number,
+        actions: PropTypes.object,
+        headers: PropTypes.object,
+        searchFilter: PropTypes.string,
+        json: PropTypes.oneOfType([
+          PropTypes.string,
+          PropTypes.object,
+          PropTypes.array,
+          PropTypes.bool,
+          PropTypes.number,
+        ]),
+        expandedNodes: PropTypes.instanceOf(Set),
+      };
+    }
+
+    constructor(props) {
+      super(props);
+
+      this.state = {
+        json: props.json,
+        expandedNodes: props.expandedNodes,
+        jsonText: props.jsonText,
+        activeTab: props.activeTab,
+      };
+
+      this.onTabChanged = this.onTabChanged.bind(this);
+    }
+
+    onTabChanged(index) {
+      this.setState({ activeTab: index });
+
+      // Send notification event to the window. This is useful for tests.
+      window.dispatchEvent(new CustomEvent("TabChanged"));
+    }
+
+    render() {
+      return Tabs(
+        {
+          activeTab: this.state.activeTab,
+          onAfterChange: this.onTabChanged,
+          tall: true,
+        },
+        TabPanel(
+          {
+            id: "json",
+            className: "json",
+            title: JSONView.Locale["jsonViewer.tab.JSON"],
+          },
+          JsonPanel({
+            data: this.state.json,
+            expandedNodes: this.state.expandedNodes,
+            actions: this.props.actions,
+            searchFilter: this.state.searchFilter,
+            dataSize: this.state.jsonText.length,
+          })
+        ),
+        TabPanel(
+          {
+            id: "rawdata",
+            className: "rawdata",
+            title: JSONView.Locale["jsonViewer.tab.RawData"],
+          },
+          TextPanel({
+            isValidJson:
+              !(this.state.json instanceof Error) &&
+              document.readyState != "loading",
+            data: this.state.jsonText,
+            actions: this.props.actions,
+          })
+        ),
+        TabPanel(
+          {
+            id: "headers",
+            className: "headers",
+            title: JSONView.Locale["jsonViewer.tab.Headers"],
+          },
+          HeadersPanel({
+            data: this.props.headers,
+            actions: this.props.actions,
+            searchFilter: this.props.searchFilter,
+          })
+        )
+      );
+    }
+  }
+
+  // Exports from this module
+  exports.MainTabbedArea = MainTabbedArea;
+});
diff --git a/devtools/client/jsonview/components/SearchBox.js b/devtools/client/jsonview/components/SearchBox.js
new file mode 100644
index 0000000000..cb736db85b
--- /dev/null
+++ b/devtools/client/jsonview/components/SearchBox.js
@@ -0,0 +1,102 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+define(function (require, exports, module) {
+  const { Component } = require("devtools/client/shared/vendor/react");
+  const PropTypes = require("devtools/client/shared/vendor/react-prop-types");
+  const dom = require("devtools/client/shared/vendor/react-dom-factories");
+
+  const { input, div, button } = dom;
+
+  // For smooth incremental searching (in case the user is typing quickly).
+  const searchDelay = 250;
+
+  /**
+   * This object represents a search box located at the
+   * top right corner of the application.
+   */
+  class SearchBox extends Component {
+    static get propTypes() {
+      return {
+        actions: PropTypes.object,
+        value: PropTypes.toString,
+      };
+    }
+
+    constructor(props) {
+      super(props);
+      this.onSearch = this.onSearch.bind(this);
+      this.doSearch = this.doSearch.bind(this);
+      this.onClearButtonClick = this.onClearButtonClick.bind(this);
+      this.onKeyDown = this.onKeyDown.bind(this);
+
+      this.state = {
+        value: props.value || "",
+      };
+    }
+
+    onSearch(event) {
+      this.setState({
+        value: event.target.value,
+      });
+      const searchBox = event.target;
+      const win = searchBox.ownerDocument.defaultView;
+
+      if (this.searchTimeout) {
+        win.clearTimeout(this.searchTimeout);
+      }
+
+      const callback = this.doSearch.bind(this, searchBox);
+      this.searchTimeout = win.setTimeout(callback, searchDelay);
+    }
+
+    doSearch(searchBox) {
+      this.props.actions.onSearch(searchBox.value);
+    }
+
+    onClearButtonClick() {
+      this.setState({ value: "" });
+      this.props.actions.onSearch("");
+      if (this._searchBoxRef) {
+        this._searchBoxRef.focus();
+      }
+    }
+
+    onKeyDown(e) {
+      switch (e.key) {
+        case "Escape":
+          e.preventDefault();
+          this.onClearButtonClick();
+          break;
+      }
+    }
+
+    render() {
+      const { value } = this.state;
+      return div(
+        { className: "devtools-searchbox" },
+        input({
+          className: "searchBox devtools-filterinput",
+          placeholder: JSONView.Locale["jsonViewer.filterJSON"],
+          onChange: this.onSearch,
+          onKeyDown: this.onKeyDown,
+          value,
+          ref: c => {
+            this._searchBoxRef = c;
+          },
+        }),
+        button({
+          className: "devtools-searchinput-clear",
+          hidden: !value,
+          onClick: this.onClearButtonClick,
+        })
+      );
+    }
+  }
+
+  // Exports from this module
+  exports.SearchBox = SearchBox;
+});
diff --git a/devtools/client/jsonview/components/TextPanel.js b/devtools/client/jsonview/components/TextPanel.js
new file mode 100644
index 0000000000..a830d9d01b
--- /dev/null
+++ b/devtools/client/jsonview/components/TextPanel.js
@@ -0,0 +1,52 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+define(function (require, exports, module) {
+  const { Component } = require("devtools/client/shared/vendor/react");
+  const PropTypes = require("devtools/client/shared/vendor/react-prop-types");
+  const dom = require("devtools/client/shared/vendor/react-dom-factories");
+  const { createFactories } = require("devtools/client/shared/react-utils");
+  const { TextToolbar } = createFactories(
+    require("devtools/client/jsonview/components/TextToolbar")
+  );
+  const { LiveText } = createFactories(
+    require("devtools/client/jsonview/components/LiveText")
+  );
+  const { div } = dom;
+
+  /**
+   * This template represents the 'Raw Data' panel displaying
+   * JSON as a text received from the server.
+   */
+  class TextPanel extends Component {
+    static get propTypes() {
+      return {
+        isValidJson: PropTypes.bool,
+        actions: PropTypes.object,
+        data: PropTypes.instanceOf(Text),
+      };
+    }
+
+    constructor(props) {
+      super(props);
+      this.state = {};
+    }
+
+    render() {
+      return div(
+        { className: "textPanelBox tab-panel-inner" },
+        TextToolbar({
+          actions: this.props.actions,
+          isValidJson: this.props.isValidJson,
+        }),
+        div({ className: "panelContent" }, LiveText({ data: this.props.data }))
+      );
+    }
+  }
+
+  // Exports from this module
+  exports.TextPanel = TextPanel;
+});
diff --git a/devtools/client/jsonview/components/TextToolbar.js b/devtools/client/jsonview/components/TextToolbar.js
new file mode 100644
index 0000000000..0ab16ef192
--- /dev/null
+++ b/devtools/client/jsonview/components/TextToolbar.js
@@ -0,0 +1,80 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+define(function (require, exports, module) {
+  const { Component } = require("devtools/client/shared/vendor/react");
+  const PropTypes = require("devtools/client/shared/vendor/react-prop-types");
+  const { createFactories } = require("devtools/client/shared/react-utils");
+  const { Toolbar, ToolbarButton } = createFactories(
+    require("devtools/client/jsonview/components/reps/Toolbar")
+  );
+
+  /**
+   * This object represents a toolbar displayed within the
+   * 'Raw Data' panel.
+   */
+  class TextToolbar extends Component {
+    static get propTypes() {
+      return {
+        actions: PropTypes.object,
+        isValidJson: PropTypes.bool,
+      };
+    }
+
+    constructor(props) {
+      super(props);
+      this.onPrettify = this.onPrettify.bind(this);
+      this.onSave = this.onSave.bind(this);
+      this.onCopy = this.onCopy.bind(this);
+    }
+
+    // Commands
+
+    onPrettify(event) {
+      this.props.actions.onPrettify();
+    }
+
+    onSave(event) {
+      this.props.actions.onSaveJson();
+    }
+
+    onCopy(event) {
+      this.props.actions.onCopyJson();
+    }
+
+    render() {
+      return Toolbar(
+        {},
+        ToolbarButton(
+          {
+            className: "btn save",
+            onClick: this.onSave,
+          },
+          JSONView.Locale["jsonViewer.Save"]
+        ),
+        ToolbarButton(
+          {
+            className: "btn copy",
+            onClick: this.onCopy,
+          },
+          JSONView.Locale["jsonViewer.Copy"]
+        ),
+        this.props.isValidJson
+          ? ToolbarButton(
+              {
+                className: "btn prettyprint",
+                onClick: this.onPrettify,
+              },
+              JSONView.Locale["jsonViewer.PrettyPrint"]
+            )
+          : null
+      );
+    }
+  }
+
+  // Exports from this module
+  exports.TextToolbar = TextToolbar;
+});
diff --git a/devtools/client/jsonview/components/moz.build b/devtools/client/jsonview/components/moz.build
new file mode 100644
index 0000000000..8cb9dc8e87
--- /dev/null
+++ b/devtools/client/jsonview/components/moz.build
@@ -0,0 +1,20 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+DIRS += ["reps"]
+
+DevToolsModules(
+    "Headers.js",
+    "HeadersPanel.js",
+    "HeadersToolbar.js",
+    "JsonPanel.js",
+    "JsonToolbar.js",
+    "LiveText.js",
+    "MainTabbedArea.js",
+    "SearchBox.js",
+    "TextPanel.js",
+    "TextToolbar.js",
+)
diff --git a/devtools/client/jsonview/components/reps/Toolbar.js b/devtools/client/jsonview/components/reps/Toolbar.js
new file mode 100644
index 0000000000..458acf236f
--- /dev/null
+++ b/devtools/client/jsonview/components/reps/Toolbar.js
@@ -0,0 +1,48 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+define(function (require, exports, module) {
+  const { Component } = require("devtools/client/shared/vendor/react");
+  const PropTypes = require("devtools/client/shared/vendor/react-prop-types");
+  const dom = require("devtools/client/shared/vendor/react-dom-factories");
+
+  /**
+   * Renders a simple toolbar.
+   */
+  class Toolbar extends Component {
+    static get propTypes() {
+      return {
+        children: PropTypes.oneOfType([PropTypes.array, PropTypes.element]),
+      };
+    }
+
+    render() {
+      return dom.div({ className: "toolbar" }, this.props.children);
+    }
+  }
+
+  /**
+   * Renders a simple toolbar button.
+   */
+  class ToolbarButton extends Component {
+    static get propTypes() {
+      return {
+        active: PropTypes.bool,
+        disabled: PropTypes.bool,
+        children: PropTypes.string,
+      };
+    }
+
+    render() {
+      const props = Object.assign({ className: "btn" }, this.props);
+      return dom.button(props, this.props.children);
+    }
+  }
+
+  // Exports from this module
+  exports.Toolbar = Toolbar;
+  exports.ToolbarButton = ToolbarButton;
+});
diff --git a/devtools/client/jsonview/components/reps/moz.build b/devtools/client/jsonview/components/reps/moz.build
new file mode 100644
index 0000000000..ba39d7767b
--- /dev/null
+++ b/devtools/client/jsonview/components/reps/moz.build
@@ -0,0 +1,9 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+DevToolsModules(
+    "Toolbar.js",
+)
diff --git a/devtools/client/jsonview/converter-child.js b/devtools/client/jsonview/converter-child.js
new file mode 100644
index 0000000000..1e14e8dacb
--- /dev/null
+++ b/devtools/client/jsonview/converter-child.js
@@ -0,0 +1,419 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+const {
+  getTheme,
+  addThemeObserver,
+  removeThemeObserver,
+} = require("resource://devtools/client/shared/theme.js");
+
+const BinaryInput = Components.Constructor(
+  "@mozilla.org/binaryinputstream;1",
+  "nsIBinaryInputStream",
+  "setInputStream"
+);
+const BufferStream = Components.Constructor(
+  "@mozilla.org/io/arraybuffer-input-stream;1",
+  "nsIArrayBufferInputStream",
+  "setData"
+);
+
+const kCSP = "default-src 'none' ; script-src resource:; ";
+
+// Localization
+loader.lazyGetter(this, "jsonViewStrings", () => {
+  return Services.strings.createBundle(
+    "chrome://devtools/locale/jsonview.properties"
+  );
+});
+
+/**
+ * This object detects 'application/vnd.mozilla.json.view' content type
+ * and converts it into a JSON Viewer application that allows simple
+ * JSON inspection.
+ *
+ * Inspired by JSON View: https://github.com/bhollis/jsonview/
+ */
+function Converter() {}
+
+Converter.prototype = {
+  QueryInterface: ChromeUtils.generateQI([
+    "nsIStreamConverter",
+    "nsIStreamListener",
+    "nsIRequestObserver",
+  ]),
+
+  get wrappedJSObject() {
+    return this;
+  },
+
+  /**
+   * This component works as such:
+   * 1. asyncConvertData captures the listener
+   * 2. onStartRequest fires, initializes stuff, modifies the listener
+   *    to match our output type
+   * 3. onDataAvailable decodes and inserts data into a text node
+   * 4. onStopRequest flushes data and spits back to the listener
+   * 5. convert does nothing, it's just the synchronous version
+   *    of asyncConvertData
+   */
+  convert(fromStream, fromType, toType, ctx) {
+    return fromStream;
+  },
+
+  asyncConvertData(fromType, toType, listener, ctx) {
+    this.listener = listener;
+  },
+  getConvertedType(fromType, channel) {
+    return "text/html";
+  },
+
+  onDataAvailable(request, inputStream, offset, count) {
+    // Decode and insert data.
+    const buffer = new ArrayBuffer(count);
+    new BinaryInput(inputStream).readArrayBuffer(count, buffer);
+    this.decodeAndInsertBuffer(buffer);
+  },
+
+  onStartRequest(request) {
+    // Set the content type to HTML in order to parse the doctype, styles
+    // and scripts. The JSON will be manually inserted as text.
+    request.QueryInterface(Ci.nsIChannel);
+    request.contentType = "text/html";
+
+    const headers = getHttpHeaders(request);
+
+    // Enforce strict CSP:
+    try {
+      request.QueryInterface(Ci.nsIHttpChannel);
+      request.setResponseHeader("Content-Security-Policy", kCSP, false);
+      request.setResponseHeader(
+        "Content-Security-Policy-Report-Only",
+        "",
+        false
+      );
+    } catch (ex) {
+      // If this is not an HTTP channel we can't and won't do anything.
+    }
+
+    // Don't honor the charset parameter and use UTF-8 (see bug 741776).
+    request.contentCharset = "UTF-8";
+    this.decoder = new TextDecoder("UTF-8");
+
+    // Changing the content type breaks saving functionality. Fix it.
+    fixSave(request);
+
+    // Because content might still have a reference to this window,
+    // force setting it to a null principal to avoid it being same-
+    // origin with (other) content.
+    request.loadInfo.resetPrincipalToInheritToNullPrincipal();
+
+    // Start the request.
+    this.listener.onStartRequest(request);
+
+    // Initialize stuff.
+    const win = getWindowForRequest(request);
+    if (!win || !Components.isSuccessCode(request.status)) {
+      return;
+    }
+
+    // We compare actual pointer identities here rather than using .equals(),
+    // because if things went correctly then the document must have exactly
+    // the principal we reset it to above. If not, something went wrong.
+    if (win.document.nodePrincipal != request.loadInfo.principalToInherit) {
+      // Whatever that document is, it's not ours.
+      request.cancel(Cr.NS_BINDING_ABORTED);
+      return;
+    }
+
+    this.data = exportData(win, headers);
+    insertJsonData(win, this.data.json);
+    win.addEventListener("contentMessage", onContentMessage, false, true);
+    keepThemeUpdated(win);
+
+    // Send the initial HTML code.
+    const buffer = new TextEncoder().encode(initialHTML(win.document)).buffer;
+    const stream = new BufferStream(buffer, 0, buffer.byteLength);
+    this.listener.onDataAvailable(request, stream, 0, stream.available());
+  },
+
+  onStopRequest(request, statusCode) {
+    // Flush data if we haven't been canceled.
+    if (Components.isSuccessCode(statusCode)) {
+      this.decodeAndInsertBuffer(new ArrayBuffer(0), true);
+    }
+
+    // Stop the request.
+    this.listener.onStopRequest(request, statusCode);
+    this.listener = null;
+    this.decoder = null;
+    this.data = null;
+  },
+
+  // Decodes an ArrayBuffer into a string and inserts it into the page.
+  decodeAndInsertBuffer(buffer, flush = false) {
+    // Decode the buffer into a string.
+    const data = this.decoder.decode(buffer, { stream: !flush });
+
+    // Using `appendData` instead of `textContent +=` is important to avoid
+    // repainting previous data.
+    this.data.json.appendData(data);
+  },
+};
+
+// Lets "save as" save the original JSON, not the viewer.
+// To save with the proper extension we need the original content type,
+// which has been replaced by application/vnd.mozilla.json.view
+function fixSave(request) {
+  let match;
+  if (request instanceof Ci.nsIHttpChannel) {
+    try {
+      const header = request.getResponseHeader("Content-Type");
+      match = header.match(/^(application\/(?:[^;]+\+)?json)(?:;|$)/);
+    } catch (err) {
+      // Handled below
+    }
+  } else {
+    const uri = request.QueryInterface(Ci.nsIChannel).URI.spec;
+    match = uri.match(/^data:(application\/(?:[^;,]+\+)?json)[;,]/);
+  }
+  let originalType;
+  if (match) {
+    originalType = match[1];
+  } else {
+    originalType = "application/json";
+  }
+  request.QueryInterface(Ci.nsIWritablePropertyBag);
+  request.setProperty("contentType", originalType);
+}
+
+function getHttpHeaders(request) {
+  const headers = {
+    response: [],
+    request: [],
+  };
+  // The request doesn't have to be always nsIHttpChannel
+  // (e.g. in case of data: URLs)
+  if (request instanceof Ci.nsIHttpChannel) {
+    request.visitResponseHeaders({
+      visitHeader(name, value) {
+        headers.response.push({ name, value });
+      },
+    });
+    request.visitRequestHeaders({
+      visitHeader(name, value) {
+        headers.request.push({ name, value });
+      },
+    });
+  }
+  return headers;
+}
+
+let jsonViewStringDict = null;
+function getAllStrings() {
+  if (!jsonViewStringDict) {
+    jsonViewStringDict = {};
+    for (const string of jsonViewStrings.getSimpleEnumeration()) {
+      jsonViewStringDict[string.key] = string.value;
+    }
+  }
+  return jsonViewStringDict;
+}
+
+// The two following methods are duplicated from NetworkHelper.sys.mjs
+// to avoid pulling the whole NetworkHelper as a dependency during
+// initialization.
+
+/**
+ * Gets the nsIDOMWindow that is associated with request.
+ *
+ * @param nsIHttpChannel request
+ * @returns nsIDOMWindow or null
+ */
+function getWindowForRequest(request) {
+  try {
+    return getRequestLoadContext(request).associatedWindow;
+  } catch (ex) {
+    // On some request notificationCallbacks and loadGroup are both null,
+    // so that we can't retrieve any nsILoadContext interface.
+    // Fallback on nsILoadInfo to try to retrieve the request's window.
+    // (this is covered by test_network_get.html and its CSS request)
+    return request.loadInfo.loadingDocument?.defaultView;
+  }
+}
+
+/**
+ * Gets the nsILoadContext that is associated with request.
+ *
+ * @param nsIHttpChannel request
+ * @returns nsILoadContext or null
+ */
+function getRequestLoadContext(request) {
+  try {
+    return request.notificationCallbacks.getInterface(Ci.nsILoadContext);
+  } catch (ex) {
+    // Ignore.
+  }
+
+  try {
+    return request.loadGroup.notificationCallbacks.getInterface(
+      Ci.nsILoadContext
+    );
+  } catch (ex) {
+    // Ignore.
+  }
+
+  return null;
+}
+
+// Exports variables that will be accessed by the non-privileged scripts.
+function exportData(win, headers) {
+  const json = new win.Text();
+  const JSONView = Cu.cloneInto(
+    {
+      headers,
+      json,
+      readyState: "uninitialized",
+      Locale: getAllStrings(),
+    },
+    win,
+    {
+      wrapReflectors: true,
+    }
+  );
+  try {
+    Object.defineProperty(Cu.waiveXrays(win), "JSONView", {
+      value: JSONView,
+      configurable: true,
+      enumerable: true,
+      writable: true,
+    });
+  } catch (error) {
+    console.error(error);
+  }
+  return { json };
+}
+
+// Builds an HTML string that will be used to load stylesheets and scripts.
+function initialHTML(doc) {
+  // Creates an element with the specified type, attributes and children.
+  function element(type, attributes = {}, children = []) {
+    const el = doc.createElement(type);
+    for (const [attr, value] of Object.entries(attributes)) {
+      el.setAttribute(attr, value);
+    }
+    el.append(...children);
+    return el;
+  }
+
+  let os;
+  const platform = Services.appinfo.OS;
+  if (platform.startsWith("WINNT")) {
+    os = "win";
+  } else if (platform.startsWith("Darwin")) {
+    os = "mac";
+  } else {
+    os = "linux";
+  }
+
+  const baseURI = "resource://devtools-client-jsonview/";
+
+  return (
+    "<!DOCTYPE html>\n" +
+    element(
+      "html",
+      {
+        platform: os,
+        class: "theme-" + getTheme(),
+        dir: Services.locale.isAppLocaleRTL ? "rtl" : "ltr",
+      },
+      [
+        element("head", {}, [
+          element("meta", {
+            "http-equiv": "Content-Security-Policy",
+            content: kCSP,
+          }),
+          element("link", {
+            rel: "stylesheet",
+            type: "text/css",
+            href: "chrome://devtools-jsonview-styles/content/main.css",
+          }),
+        ]),
+        element("body", {}, [
+          element("div", { id: "content" }, [element("div", { id: "json" })]),
+          element("script", {
+            src: baseURI + "lib/require.js",
+            "data-main": baseURI + "viewer-config.js",
+          }),
+        ]),
+      ]
+    ).outerHTML
+  );
+}
+
+// We insert the received data into a text node, which should be appended into
+// the #json element so that the JSON is still displayed even if JS is disabled.
+// However, the HTML parser is not synchronous, so this function uses a mutation
+// observer to detect the creation of the element. Then the text node is appended.
+function insertJsonData(win, json) {
+  new win.MutationObserver(function (mutations, observer) {
+    for (const { target, addedNodes } of mutations) {
+      if (target.nodeType == 1 && target.id == "content") {
+        for (const node of addedNodes) {
+          if (node.nodeType == 1 && node.id == "json") {
+            observer.disconnect();
+            node.append(json);
+            return;
+          }
+        }
+      }
+    }
+  }).observe(win.document, {
+    childList: true,
+    subtree: true,
+  });
+}
+
+function keepThemeUpdated(win) {
+  const listener = function () {
+    win.document.documentElement.className = "theme-" + getTheme();
+  };
+  addThemeObserver(listener);
+  win.addEventListener(
+    "unload",
+    function (event) {
+      removeThemeObserver(listener);
+      win = null;
+    },
+    { once: true }
+  );
+}
+
+// Chrome <-> Content communication
+function onContentMessage(e) {
+  // Do not handle events from different documents.
+  const win = this;
+  if (win != e.target) {
+    return;
+  }
+
+  const value = e.detail.value;
+  switch (e.detail.type) {
+    case "save":
+      win.docShell.messageManager.sendAsyncMessage(
+        "devtools:jsonview:save",
+        value
+      );
+  }
+}
+
+function createInstance() {
+  return new Converter();
+}
+
+exports.JsonViewService = {
+  createInstance,
+};
diff --git a/devtools/client/jsonview/css/general.css b/devtools/client/jsonview/css/general.css
new file mode 100644
index 0000000000..1fb15fdfc3
--- /dev/null
+++ b/devtools/client/jsonview/css/general.css
@@ -0,0 +1,48 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/******************************************************************************/
+/* General */
+
+html, body, #content {
+  height: 100%;
+}
+
+body {
+  color: var(--theme-body-color);
+  background-color: var(--theme-body-background);
+  padding: 0;
+  margin: 0;
+}
+
+*:focus {
+  outline: none !important;
+}
+
+pre {
+  background-color: white;
+  border: none;
+  font-family: var(--monospace-font-family);
+}
+
+#content {
+  display: flow-root;
+}
+
+#json {
+  margin: 8px;
+  white-space: pre-wrap;
+}
+
+/******************************************************************************/
+/* Dark Theme */
+
+body.theme-dark {
+  color: var(--theme-body-color);
+  background-color: var(--theme-body-background);
+}
+
+.theme-dark pre {
+  background-color: var(--theme-body-background);
+}
diff --git a/devtools/client/jsonview/css/headers-panel.css b/devtools/client/jsonview/css/headers-panel.css
new file mode 100644
index 0000000000..b37340b51a
--- /dev/null
+++ b/devtools/client/jsonview/css/headers-panel.css
@@ -0,0 +1,66 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/******************************************************************************/
+/* Headers Panel */
+
+.headersPanelBox {
+  height: 100%;
+}
+
+.headersPanelBox .netInfoHeadersTable {
+  overflow: auto;
+  height: 100%;
+}
+
+.headersPanelBox .netHeadersGroup {
+  padding: 10px;
+}
+
+.headersPanelBox td {
+  vertical-align: bottom;
+}
+
+.headersPanelBox .netInfoHeadersGroup {
+  color: var(--theme-toolbar-color);
+  margin-bottom: 10px;
+  border-bottom: 1px solid var(--theme-splitter-color);
+  padding-top: 8px;
+  padding-bottom: 4px;
+  font-weight: bold;
+  user-select: none;
+}
+
+.headersPanelBox .netInfoParamValue {
+  word-wrap: break-word;
+}
+
+.headersPanelBox .netInfoParamName {
+  padding: 2px 10px 0 0;
+  font-weight: bold;
+  vertical-align: top;
+  text-align: right;
+  white-space: nowrap;
+}
+
+/******************************************************************************/
+/* Theme colors have been generated/copied from Network Panel's header view */
+
+/* Light Theme */
+.theme-light .netInfoParamName {
+  color: var(--theme-highlight-red);
+}
+
+.theme-light .netInfoParamValue {
+  color: var(--theme-highlight-purple);
+}
+
+/* Dark Theme */
+.theme-dark .netInfoParamName {
+  color: var(--theme-highlight-purple);
+}
+
+.theme-dark .netInfoParamValue {
+  color: var(--theme-highlight-gray);
+}
diff --git a/devtools/client/jsonview/css/json-panel.css b/devtools/client/jsonview/css/json-panel.css
new file mode 100644
index 0000000000..98c228e87e
--- /dev/null
+++ b/devtools/client/jsonview/css/json-panel.css
@@ -0,0 +1,18 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/******************************************************************************/
+/* JSON Panel */
+
+.jsonPrimitiveValue,
+.jsonParseError {
+  font-size: 12px;
+  font-family: Lucida Grande, Tahoma, sans-serif;
+  line-height: 15px;
+  padding: 10px;
+}
+
+.jsonParseError {
+  color: var(--theme-text-color-error);
+}
diff --git a/devtools/client/jsonview/css/main.css b/devtools/client/jsonview/css/main.css
new file mode 100644
index 0000000000..996b6b7a4d
--- /dev/null
+++ b/devtools/client/jsonview/css/main.css
@@ -0,0 +1,44 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+@import "chrome://devtools/skin/variables.css";
+@import "chrome://devtools/skin/common.css";
+@import "chrome://devtools/skin/toolbars.css";
+
+@import "chrome://devtools/content/shared/components/tree/TreeView.css";
+@import "chrome://devtools/content/shared/components/tabs/Tabs.css";
+
+@import "general.css";
+@import "search-box.css";
+@import "toolbar.css";
+@import "json-panel.css";
+@import "text-panel.css";
+@import "headers-panel.css";
+
+/******************************************************************************/
+/* Panel Content */
+
+.tab-panel-inner {
+  display: flex;
+  flex-direction: column;
+  height: 100%;
+}
+
+.panelContent {
+  direction: ltr;
+  overflow-y: auto;
+  width: 100%;
+  flex: 1;
+}
+
+/* The tree takes the entire horizontal space within the panel content. */
+.panelContent .treeTable {
+  width: 100%;
+  font-family: var(--monospace-font-family);
+}
+
+/* Make sure there is a little space between label and value columns. */
+.panelContent .treeTable .treeLabelCell {
+  padding-right: 17px;
+}
diff --git a/devtools/client/jsonview/css/moz.build b/devtools/client/jsonview/css/moz.build
new file mode 100644
index 0000000000..53ebea91b0
--- /dev/null
+++ b/devtools/client/jsonview/css/moz.build
@@ -0,0 +1,15 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+DevToolsModules(
+    "general.css",
+    "headers-panel.css",
+    "json-panel.css",
+    "main.css",
+    "search-box.css",
+    "text-panel.css",
+    "toolbar.css",
+)
diff --git a/devtools/client/jsonview/css/search-box.css b/devtools/client/jsonview/css/search-box.css
new file mode 100644
index 0000000000..25828c6b76
--- /dev/null
+++ b/devtools/client/jsonview/css/search-box.css
@@ -0,0 +1,20 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/******************************************************************************/
+/* Search Box */
+
+.devtools-searchbox {
+  background-color: var(--theme-body-background);
+}
+
+.devtools-filterinput {
+  margin-inline-start: auto; /* Align to the right */
+}
+
+/* JSONView doesn't load dark-theme.css */
+.theme-dark .devtools-filterinput {
+  background-color: rgba(24, 29, 32, 1);
+  color: rgba(184, 200, 217, 1);
+}
diff --git a/devtools/client/jsonview/css/text-panel.css b/devtools/client/jsonview/css/text-panel.css
new file mode 100644
index 0000000000..b656918898
--- /dev/null
+++ b/devtools/client/jsonview/css/text-panel.css
@@ -0,0 +1,18 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/******************************************************************************/
+/* Text Panel */
+
+.textPanelBox {
+  height: 100%;
+}
+
+.textPanelBox pre {
+  margin: 8px;
+  white-space: pre-wrap;
+  overflow-wrap: break-word;
+  font-family: var(--monospace-font-family);
+  color: var(--theme-text-color-strong);
+}
diff --git a/devtools/client/jsonview/css/toolbar.css b/devtools/client/jsonview/css/toolbar.css
new file mode 100644
index 0000000000..58349d887c
--- /dev/null
+++ b/devtools/client/jsonview/css/toolbar.css
@@ -0,0 +1,39 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/******************************************************************************/
+/* Toolbar */
+
+.toolbar {
+  display: flex;
+  height: 22px;
+  padding: 1px;
+  padding-inline-start: 2px;
+  background: var(--theme-toolbar-background);
+  border-bottom: 1px solid var(--theme-splitter-color);
+}
+
+.toolbar .btn {
+  margin-inline-start: 5px;
+  color: var(--theme-body-color);
+  background: var(--toolbarbutton-background);
+  border: none;
+  text-decoration: none;
+  display: inline-block;
+  text-align: center;
+  white-space: nowrap;
+  vertical-align: middle;
+  cursor: pointer;
+  user-select: none;
+  padding: 0 3px;
+  border-radius: 2px;
+}
+
+.toolbar .btn:hover {
+  background: var(--toolbarbutton-hover-background);
+}
+
+.toolbar .btn:not([disabled]):hover:active {
+  background-color: var(--theme-selection-background-hover);
+}
diff --git a/devtools/client/jsonview/json-viewer.js b/devtools/client/jsonview/json-viewer.js
new file mode 100644
index 0000000000..139ed31f61
--- /dev/null
+++ b/devtools/client/jsonview/json-viewer.js
@@ -0,0 +1,203 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+define(function (require, exports, module) {
+  const { render } = require("devtools/client/shared/vendor/react-dom");
+  const { createFactories } = require("devtools/client/shared/react-utils");
+  const { MainTabbedArea } = createFactories(
+    require("devtools/client/jsonview/components/MainTabbedArea")
+  );
+  const TreeViewClass = require("devtools/client/shared/components/tree/TreeView");
+
+  const AUTO_EXPAND_MAX_SIZE = 100 * 1024;
+  const AUTO_EXPAND_MAX_LEVEL = 7;
+
+  let prettyURL;
+  let theApp;
+
+  // Application state object.
+  const input = {
+    jsonText: JSONView.json,
+    jsonPretty: null,
+    headers: JSONView.headers,
+    activeTab: 0,
+    prettified: false,
+    expandedNodes: new Set(),
+  };
+
+  /**
+   * Application actions/commands. This list implements all commands
+   * available for the JSON viewer.
+   */
+  input.actions = {
+    onCopyJson() {
+      const text = input.prettified ? input.jsonPretty : input.jsonText;
+      copyString(text.textContent);
+    },
+
+    onSaveJson() {
+      if (input.prettified && !prettyURL) {
+        prettyURL = URL.createObjectURL(
+          new window.Blob([input.jsonPretty.textContent])
+        );
+      }
+      dispatchEvent("save", input.prettified ? prettyURL : null);
+    },
+
+    onCopyHeaders() {
+      let value = "";
+      const isWinNT =
+        document.documentElement.getAttribute("platform") === "win";
+      const eol = isWinNT ? "\r\n" : "\n";
+
+      const responseHeaders = input.headers.response;
+      for (let i = 0; i < responseHeaders.length; i++) {
+        const header = responseHeaders[i];
+        value += header.name + ": " + header.value + eol;
+      }
+
+      value += eol;
+
+      const requestHeaders = input.headers.request;
+      for (let i = 0; i < requestHeaders.length; i++) {
+        const header = requestHeaders[i];
+        value += header.name + ": " + header.value + eol;
+      }
+
+      copyString(value);
+    },
+
+    onSearch(value) {
+      theApp.setState({ searchFilter: value });
+    },
+
+    onPrettify(data) {
+      if (input.json instanceof Error) {
+        // Cannot prettify invalid JSON
+        return;
+      }
+      if (input.prettified) {
+        theApp.setState({ jsonText: input.jsonText });
+      } else {
+        if (!input.jsonPretty) {
+          input.jsonPretty = new Text(JSON.stringify(input.json, null, "  "));
+        }
+        theApp.setState({ jsonText: input.jsonPretty });
+      }
+
+      input.prettified = !input.prettified;
+    },
+
+    onCollapse(data) {
+      input.expandedNodes.clear();
+      theApp.forceUpdate();
+    },
+
+    onExpand(data) {
+      input.expandedNodes = TreeViewClass.getExpandedNodes(input.json);
+      theApp.setState({ expandedNodes: input.expandedNodes });
+    },
+  };
+
+  /**
+   * Helper for copying a string to the clipboard.
+   *
+   * @param {String} string The text to be copied.
+   */
+  function copyString(string) {
+    document.addEventListener(
+      "copy",
+      event => {
+        event.clipboardData.setData("text/plain", string);
+        event.preventDefault();
+      },
+      { once: true }
+    );
+
+    document.execCommand("copy", false, null);
+  }
+
+  /**
+   * Helper for dispatching an event. It's handled in chrome scope.
+   *
+   * @param {String} type Event detail type
+   * @param {Object} value Event detail value
+   */
+  function dispatchEvent(type, value) {
+    const data = {
+      detail: {
+        type,
+        value,
+      },
+    };
+
+    const contentMessageEvent = new CustomEvent("contentMessage", data);
+    window.dispatchEvent(contentMessageEvent);
+  }
+
+  /**
+   * Render the main application component. It's the main tab bar displayed
+   * at the top of the window. This component also represents ReacJS root.
+   */
+  const content = document.getElementById("content");
+  const promise = (async function parseJSON() {
+    if (document.readyState == "loading") {
+      // If the JSON has not been loaded yet, render the Raw Data tab first.
+      input.json = {};
+      input.activeTab = 1;
+      return new Promise(resolve => {
+        document.addEventListener("DOMContentLoaded", resolve, { once: true });
+      })
+        .then(parseJSON)
+        .then(async () => {
+          // Now update the state and switch to the JSON tab.
+          await appIsReady;
+          theApp.setState({
+            activeTab: 0,
+            json: input.json,
+            expandedNodes: input.expandedNodes,
+          });
+        });
+    }
+
+    // If the JSON has been loaded, parse it immediately before loading the app.
+    const jsonString = input.jsonText.textContent;
+    try {
+      input.json = JSON.parse(jsonString);
+    } catch (err) {
+      input.json = err;
+    }
+
+    // Expand the document by default if its size isn't bigger than 100KB.
+    if (
+      !(input.json instanceof Error) &&
+      jsonString.length <= AUTO_EXPAND_MAX_SIZE
+    ) {
+      input.expandedNodes = TreeViewClass.getExpandedNodes(input.json, {
+        maxLevel: AUTO_EXPAND_MAX_LEVEL,
+      });
+    }
+    return undefined;
+  })();
+
+  const appIsReady = new Promise(resolve => {
+    render(MainTabbedArea(input), content, function () {
+      theApp = this;
+      resolve();
+
+      // Send readyState change notification event to the window. Can be useful for
+      // tests as well as extensions.
+      JSONView.readyState = "interactive";
+      window.dispatchEvent(new CustomEvent("AppReadyStateChange"));
+
+      promise.then(() => {
+        // Another readyState change notification event.
+        JSONView.readyState = "complete";
+        window.dispatchEvent(new CustomEvent("AppReadyStateChange"));
+      });
+    });
+  });
+});
diff --git a/devtools/client/jsonview/lib/moz.build b/devtools/client/jsonview/lib/moz.build
new file mode 100644
index 0000000000..461ef2e445
--- /dev/null
+++ b/devtools/client/jsonview/lib/moz.build
@@ -0,0 +1,7 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+DevToolsModules("require.js")
diff --git a/devtools/client/jsonview/lib/require.js b/devtools/client/jsonview/lib/require.js
new file mode 100644
index 0000000000..eefa4e55c8
--- /dev/null
+++ b/devtools/client/jsonview/lib/require.js
@@ -0,0 +1,2080 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * @license RequireJS 2.1.15 Copyright (c) 2010-2014, The Dojo Foundation All Rights Reserved.
+ * Available via the MIT or new BSD license.
+ * see: http://github.com/jrburke/requirejs for details
+ */
+//Not using strict: uneven strict support in browsers, #392, and causes
+//problems with requirejs.exec()/transpiler plugins that may not be strict.
+/*jslint regexp: true, nomen: true, sloppy: true */
+/*global window, navigator, document, importScripts, setTimeout, opera */
+
+var requirejs, require, define;
+(function (global) {
+    var req, s, head, baseElement, dataMain, src,
+        interactiveScript, currentlyAddingScript, mainScript, subPath,
+        version = '2.1.15',
+        commentRegExp = /(\/\*([\s\S]*?)\*\/|([^:]|^)\/\/(.*)$)/mg,
+        cjsRequireRegExp = /[^.]\s*require\s*\(\s*["']([^'"\s]+)["']\s*\)/g,
+        jsSuffixRegExp = /\.js$/,
+        currDirRegExp = /^\.\//,
+        op = Object.prototype,
+        ostring = op.toString,
+        hasOwn = op.hasOwnProperty,
+        ap = Array.prototype,
+        apsp = ap.splice,
+        isBrowser = !!(typeof window !== 'undefined' && typeof navigator !== 'undefined' && window.document),
+        isWebWorker = !isBrowser && typeof importScripts !== 'undefined',
+        //PS3 indicates loaded and complete, but need to wait for complete
+        //specifically. Sequence is 'loading', 'loaded', execution,
+        // then 'complete'. The UA check is unfortunate, but not sure how
+        //to feature test w/o causing perf issues.
+        readyRegExp = isBrowser && navigator.platform === 'PLAYSTATION 3' ?
+                      /^complete$/ : /^(complete|loaded)$/,
+        defContextName = '_',
+        //Oh the tragedy, detecting opera. See the usage of isOpera for reason.
+        isOpera = typeof opera !== 'undefined' && opera.toString() === '[object Opera]',
+        contexts = {},
+        cfg = {},
+        globalDefQueue = [],
+        useInteractive = false;
+
+    function isFunction(it) {
+        return ostring.call(it) === '[object Function]';
+    }
+
+    function isArray(it) {
+        return ostring.call(it) === '[object Array]';
+    }
+
+    /**
+     * Helper function for iterating over an array. If the func returns
+     * a true value, it will break out of the loop.
+     */
+    function each(ary, func) {
+        if (ary) {
+            var i;
+            for (i = 0; i < ary.length; i += 1) {
+                if (ary[i] && func(ary[i], i, ary)) {
+                    break;
+                }
+            }
+        }
+    }
+
+    /**
+     * Helper function for iterating over an array backwards. If the func
+     * returns a true value, it will break out of the loop.
+     */
+    function eachReverse(ary, func) {
+        if (ary) {
+            var i;
+            for (i = ary.length - 1; i > -1; i -= 1) {
+                if (ary[i] && func(ary[i], i, ary)) {
+                    break;
+                }
+            }
+        }
+    }
+
+    function hasProp(obj, prop) {
+        return hasOwn.call(obj, prop);
+    }
+
+    function getOwn(obj, prop) {
+        return hasProp(obj, prop) && obj[prop];
+    }
+
+    /**
+     * Cycles over properties in an object and calls a function for each
+     * property value. If the function returns a truthy value, then the
+     * iteration is stopped.
+     */
+    function eachProp(obj, func) {
+        var prop;
+        for (prop in obj) {
+            if (hasProp(obj, prop)) {
+                if (func(obj[prop], prop)) {
+                    break;
+                }
+            }
+        }
+    }
+
+    /**
+     * Simple function to mix in properties from source into target,
+     * but only if target does not already have a property of the same name.
+     */
+    function mixin(target, source, force, deepStringMixin) {
+        if (source) {
+            eachProp(source, function (value, prop) {
+                if (force || !hasProp(target, prop)) {
+                    if (deepStringMixin && typeof value === 'object' && value &&
+                        !isArray(value) && !isFunction(value) &&
+                        !(value instanceof RegExp)) {
+
+                        if (!target[prop]) {
+                            target[prop] = {};
+                        }
+                        mixin(target[prop], value, force, deepStringMixin);
+                    } else {
+                        target[prop] = value;
+                    }
+                }
+            });
+        }
+        return target;
+    }
+
+    //Similar to Function.prototype.bind, but the 'this' object is specified
+    //first, since it is easier to read/figure out what 'this' will be.
+    function bind(obj, fn) {
+        return function () {
+            return fn.apply(obj, arguments);
+        };
+    }
+
+    function scripts() {
+        return document.getElementsByTagName('script');
+    }
+
+    function defaultOnError(err) {
+        throw err;
+    }
+
+    //Allow getting a global that is expressed in
+    //dot notation, like 'a.b.c'.
+    function getGlobal(value) {
+        if (!value) {
+            return value;
+        }
+        var g = global;
+        each(value.split('.'), function (part) {
+            g = g[part];
+        });
+        return g;
+    }
+
+    /**
+     * Constructs an error with a pointer to an URL with more information.
+     * @param {String} id the error ID that maps to an ID on a web page.
+     * @param {String} message human readable error.
+     * @param {Error} [err] the original error, if there is one.
+     *
+     * @returns {Error}
+     */
+    function makeError(id, msg, err, requireModules) {
+        var e = new Error(msg + '\nhttp://requirejs.org/docs/errors.html#' + id);
+        e.requireType = id;
+        e.requireModules = requireModules;
+        if (err) {
+            e.originalError = err;
+        }
+        return e;
+    }
+
+    if (typeof define !== 'undefined') {
+        //If a define is already in play via another AMD loader,
+        //do not overwrite.
+        return;
+    }
+
+    if (typeof requirejs !== 'undefined') {
+        if (isFunction(requirejs)) {
+            //Do not overwrite an existing requirejs instance.
+            return;
+        }
+        cfg = requirejs;
+        requirejs = undefined;
+    }
+
+    //Allow for a require config object
+    if (typeof require !== 'undefined' && !isFunction(require)) {
+        //assume it is a config object.
+        cfg = require;
+        require = undefined;
+    }
+
+    function newContext(contextName) {
+        var inCheckLoaded, Module, context, handlers,
+            checkLoadedTimeoutId,
+            config = {
+                //Defaults. Do not set a default for map
+                //config to speed up normalize(), which
+                //will run faster if there is no default.
+                waitSeconds: 7,
+                baseUrl: './',
+                paths: {},
+                bundles: {},
+                pkgs: {},
+                shim: {},
+                config: {}
+            },
+            registry = {},
+            //registry of just enabled modules, to speed
+            //cycle breaking code when lots of modules
+            //are registered, but not activated.
+            enabledRegistry = {},
+            undefEvents = {},
+            defQueue = [],
+            defined = {},
+            urlFetched = {},
+            bundlesMap = {},
+            requireCounter = 1,
+            unnormalizedCounter = 1;
+
+        /**
+         * Trims the . and .. from an array of path segments.
+         * It will keep a leading path segment if a .. will become
+         * the first path segment, to help with module name lookups,
+         * which act like paths, but can be remapped. But the end result,
+         * all paths that use this function should look normalized.
+         * NOTE: this method MODIFIES the input array.
+         * @param {Array} ary the array of path segments.
+         */
+        function trimDots(ary) {
+            var i, part;
+            for (i = 0; i < ary.length; i++) {
+                part = ary[i];
+                if (part === '.') {
+                    ary.splice(i, 1);
+                    i -= 1;
+                } else if (part === '..') {
+                    // If at the start, or previous value is still ..,
+                    // keep them so that when converted to a path it may
+                    // still work when converted to a path, even though
+                    // as an ID it is less than ideal. In larger point
+                    // releases, may be better to just kick out an error.
+                    if (i === 0 || (i == 1 && ary[2] === '..') || ary[i - 1] === '..') {
+                        continue;
+                    } else if (i > 0) {
+                        ary.splice(i - 1, 2);
+                        i -= 2;
+                    }
+                }
+            }
+        }
+
+        /**
+         * Given a relative module name, like ./something, normalize it to
+         * a real name that can be mapped to a path.
+         * @param {String} name the relative name
+         * @param {String} baseName a real name that the name arg is relative
+         * to.
+         * @param {Boolean} applyMap apply the map config to the value. Should
+         * only be done if this normalization is for a dependency ID.
+         * @returns {String} normalized name
+         */
+        function normalize(name, baseName, applyMap) {
+            var pkgMain, mapValue, nameParts, i, j, nameSegment, lastIndex,
+                foundMap, foundI, foundStarMap, starI, normalizedBaseParts,
+                baseParts = (baseName && baseName.split('/')),
+                map = config.map,
+                starMap = map && map['*'];
+
+            //Adjust any relative paths.
+            if (name) {
+                name = name.split('/');
+                lastIndex = name.length - 1;
+
+                // If wanting node ID compatibility, strip .js from end
+                // of IDs. Have to do this here, and not in nameToUrl
+                // because node allows either .js or non .js to map
+                // to same file.
+                if (config.nodeIdCompat && jsSuffixRegExp.test(name[lastIndex])) {
+                    name[lastIndex] = name[lastIndex].replace(jsSuffixRegExp, '');
+                }
+
+                // Starts with a '.' so need the baseName
+                if (name[0].charAt(0) === '.' && baseParts) {
+                    //Convert baseName to array, and lop off the last part,
+                    //so that . matches that 'directory' and not name of the baseName's
+                    //module. For instance, baseName of 'one/two/three', maps to
+                    //'one/two/three.js', but we want the directory, 'one/two' for
+                    //this normalization.
+                    normalizedBaseParts = baseParts.slice(0, baseParts.length - 1);
+                    name = normalizedBaseParts.concat(name);
+                }
+
+                trimDots(name);
+                name = name.join('/');
+            }
+
+            //Apply map config if available.
+            if (applyMap && map && (baseParts || starMap)) {
+                nameParts = name.split('/');
+
+                outerLoop: for (i = nameParts.length; i > 0; i -= 1) {
+                    nameSegment = nameParts.slice(0, i).join('/');
+
+                    if (baseParts) {
+                        //Find the longest baseName segment match in the config.
+                        //So, do joins on the biggest to smallest lengths of baseParts.
+                        for (j = baseParts.length; j > 0; j -= 1) {
+                            mapValue = getOwn(map, baseParts.slice(0, j).join('/'));
+
+                            //baseName segment has config, find if it has one for
+                            //this name.
+                            if (mapValue) {
+                                mapValue = getOwn(mapValue, nameSegment);
+                                if (mapValue) {
+                                    //Match, update name to the new value.
+                                    foundMap = mapValue;
+                                    foundI = i;
+                                    break outerLoop;
+                                }
+                            }
+                        }
+                    }
+
+                    //Check for a star map match, but just hold on to it,
+                    //if there is a shorter segment match later in a matching
+                    //config, then favor over this star map.
+                    if (!foundStarMap && starMap && getOwn(starMap, nameSegment)) {
+                        foundStarMap = getOwn(starMap, nameSegment);
+                        starI = i;
+                    }
+                }
+
+                if (!foundMap && foundStarMap) {
+                    foundMap = foundStarMap;
+                    foundI = starI;
+                }
+
+                if (foundMap) {
+                    nameParts.splice(0, foundI, foundMap);
+                    name = nameParts.join('/');
+                }
+            }
+
+            // If the name points to a package's name, use
+            // the package main instead.
+            pkgMain = getOwn(config.pkgs, name);
+
+            return pkgMain ? pkgMain : name;
+        }
+
+        function removeScript(name) {
+            if (isBrowser) {
+                each(scripts(), function (scriptNode) {
+                    if (scriptNode.getAttribute('data-requiremodule') === name &&
+                            scriptNode.getAttribute('data-requirecontext') === context.contextName) {
+                        scriptNode.parentNode.removeChild(scriptNode);
+                        return true;
+                    }
+                });
+            }
+        }
+
+        function hasPathFallback(id) {
+            var pathConfig = getOwn(config.paths, id);
+            if (pathConfig && isArray(pathConfig) && pathConfig.length > 1) {
+                //Pop off the first array value, since it failed, and
+                //retry
+                pathConfig.shift();
+                context.require.undef(id);
+
+                //Custom require that does not do map translation, since
+                //ID is "absolute", already mapped/resolved.
+                context.makeRequire(null, {
+                    skipMap: true
+                })([id]);
+
+                return true;
+            }
+        }
+
+        //Turns a plugin!resource to [plugin, resource]
+        //with the plugin being undefined if the name
+        //did not have a plugin prefix.
+        function splitPrefix(name) {
+            var prefix,
+                index = name ? name.indexOf('!') : -1;
+            if (index > -1) {
+                prefix = name.substring(0, index);
+                name = name.substring(index + 1, name.length);
+            }
+            return [prefix, name];
+        }
+
+        /**
+         * Creates a module mapping that includes plugin prefix, module
+         * name, and path. If parentModuleMap is provided it will
+         * also normalize the name via require.normalize()
+         *
+         * @param {String} name the module name
+         * @param {String} [parentModuleMap] parent module map
+         * for the module name, used to resolve relative names.
+         * @param {Boolean} isNormalized: is the ID already normalized.
+         * This is true if this call is done for a define() module ID.
+         * @param {Boolean} applyMap: apply the map config to the ID.
+         * Should only be true if this map is for a dependency.
+         *
+         * @returns {Object}
+         */
+        function makeModuleMap(name, parentModuleMap, isNormalized, applyMap) {
+            var url, pluginModule, suffix, nameParts,
+                prefix = null,
+                parentName = parentModuleMap ? parentModuleMap.name : null,
+                originalName = name,
+                isDefine = true,
+                normalizedName = '';
+
+            //If no name, then it means it is a require call, generate an
+            //internal name.
+            if (!name) {
+                isDefine = false;
+                name = '_@r' + (requireCounter += 1);
+            }
+
+            nameParts = splitPrefix(name);
+            prefix = nameParts[0];
+            name = nameParts[1];
+
+            if (prefix) {
+                prefix = normalize(prefix, parentName, applyMap);
+                pluginModule = getOwn(defined, prefix);
+            }
+
+            //Account for relative paths if there is a base name.
+            if (name) {
+                if (prefix) {
+                    if (pluginModule && pluginModule.normalize) {
+                        //Plugin is loaded, use its normalize method.
+                        normalizedName = pluginModule.normalize(name, function (name) {
+                            return normalize(name, parentName, applyMap);
+                        });
+                    } else {
+                        // If nested plugin references, then do not try to
+                        // normalize, as it will not normalize correctly. This
+                        // places a restriction on resourceIds, and the longer
+                        // term solution is not to normalize until plugins are
+                        // loaded and all normalizations to allow for async
+                        // loading of a loader plugin. But for now, fixes the
+                        // common uses. Details in #1131
+                        normalizedName = name.indexOf('!') === -1 ?
+                                         normalize(name, parentName, applyMap) :
+                                         name;
+                    }
+                } else {
+                    //A regular module.
+                    normalizedName = normalize(name, parentName, applyMap);
+
+                    //Normalized name may be a plugin ID due to map config
+                    //application in normalize. The map config values must
+                    //already be normalized, so do not need to redo that part.
+                    nameParts = splitPrefix(normalizedName);
+                    prefix = nameParts[0];
+                    normalizedName = nameParts[1];
+                    isNormalized = true;
+
+                    url = context.nameToUrl(normalizedName);
+                }
+            }
+
+            //If the id is a plugin id that cannot be determined if it needs
+            //normalization, stamp it with a unique ID so two matching relative
+            //ids that may conflict can be separate.
+            suffix = prefix && !pluginModule && !isNormalized ?
+                     '_unnormalized' + (unnormalizedCounter += 1) :
+                     '';
+
+            return {
+                prefix: prefix,
+                name: normalizedName,
+                parentMap: parentModuleMap,
+                unnormalized: !!suffix,
+                url: url,
+                originalName: originalName,
+                isDefine: isDefine,
+                id: (prefix ?
+                        prefix + '!' + normalizedName :
+                        normalizedName) + suffix
+            };
+        }
+
+        function getModule(depMap) {
+            var id = depMap.id,
+                mod = getOwn(registry, id);
+
+            if (!mod) {
+                mod = registry[id] = new context.Module(depMap);
+            }
+
+            return mod;
+        }
+
+        function on(depMap, name, fn) {
+            var id = depMap.id,
+                mod = getOwn(registry, id);
+
+            if (hasProp(defined, id) &&
+                    (!mod || mod.defineEmitComplete)) {
+                if (name === 'defined') {
+                    fn(defined[id]);
+                }
+            } else {
+                mod = getModule(depMap);
+                if (mod.error && name === 'error') {
+                    fn(mod.error);
+                } else {
+                    mod.on(name, fn);
+                }
+            }
+        }
+
+        function onError(err, errback) {
+            var ids = err.requireModules,
+                notified = false;
+
+            if (errback) {
+                errback(err);
+            } else {
+                each(ids, function (id) {
+                    var mod = getOwn(registry, id);
+                    if (mod) {
+                        //Set error on module, so it skips timeout checks.
+                        mod.error = err;
+                        if (mod.events.error) {
+                            notified = true;
+                            mod.emit('error', err);
+                        }
+                    }
+                });
+
+                if (!notified) {
+                    req.onError(err);
+                }
+            }
+        }
+
+        /**
+         * Internal method to transfer globalQueue items to this context's
+         * defQueue.
+         */
+        function takeGlobalQueue() {
+            //Push all the globalDefQueue items into the context's defQueue
+            if (globalDefQueue.length) {
+                //Array splice in the values since the context code has a
+                //local var ref to defQueue, so cannot just reassign the one
+                //on context.
+                apsp.apply(defQueue,
+                           [defQueue.length, 0].concat(globalDefQueue));
+                globalDefQueue = [];
+            }
+        }
+
+        handlers = {
+            'require': function (mod) {
+                if (mod.require) {
+                    return mod.require;
+                } else {
+                    return (mod.require = context.makeRequire(mod.map));
+                }
+            },
+            'exports': function (mod) {
+                mod.usingExports = true;
+                if (mod.map.isDefine) {
+                    if (mod.exports) {
+                        return (defined[mod.map.id] = mod.exports);
+                    } else {
+                        return (mod.exports = defined[mod.map.id] = {});
+                    }
+                }
+            },
+            'module': function (mod) {
+                if (mod.module) {
+                    return mod.module;
+                } else {
+                    return (mod.module = {
+                        id: mod.map.id,
+                        uri: mod.map.url,
+                        config: function () {
+                            return  getOwn(config.config, mod.map.id) || {};
+                        },
+                        exports: mod.exports || (mod.exports = {})
+                    });
+                }
+            }
+        };
+
+        function cleanRegistry(id) {
+            //Clean up machinery used for waiting modules.
+            delete registry[id];
+            delete enabledRegistry[id];
+        }
+
+        function breakCycle(mod, traced, processed) {
+            var id = mod.map.id;
+
+            if (mod.error) {
+                mod.emit('error', mod.error);
+            } else {
+                traced[id] = true;
+                each(mod.depMaps, function (depMap, i) {
+                    var depId = depMap.id,
+                        dep = getOwn(registry, depId);
+
+                    //Only force things that have not completed
+                    //being defined, so still in the registry,
+                    //and only if it has not been matched up
+                    //in the module already.
+                    if (dep && !mod.depMatched[i] && !processed[depId]) {
+                        if (getOwn(traced, depId)) {
+                            mod.defineDep(i, defined[depId]);
+                            mod.check(); //pass false?
+                        } else {
+                            breakCycle(dep, traced, processed);
+                        }
+                    }
+                });
+                processed[id] = true;
+            }
+        }
+
+        function checkLoaded() {
+            var err, usingPathFallback,
+                waitInterval = config.waitSeconds * 1000,
+                //It is possible to disable the wait interval by using waitSeconds of 0.
+                expired = waitInterval && (context.startTime + waitInterval) < new Date().getTime(),
+                noLoads = [],
+                reqCalls = [],
+                stillLoading = false,
+                needCycleCheck = true;
+
+            //Do not bother if this call was a result of a cycle break.
+            if (inCheckLoaded) {
+                return;
+            }
+
+            inCheckLoaded = true;
+
+            //Figure out the state of all the modules.
+            eachProp(enabledRegistry, function (mod) {
+                var map = mod.map,
+                    modId = map.id;
+
+                //Skip things that are not enabled or in error state.
+                if (!mod.enabled) {
+                    return;
+                }
+
+                if (!map.isDefine) {
+                    reqCalls.push(mod);
+                }
+
+                if (!mod.error) {
+                    //If the module should be executed, and it has not
+                    //been inited and time is up, remember it.
+                    if (!mod.inited && expired) {
+                        if (hasPathFallback(modId)) {
+                            usingPathFallback = true;
+                            stillLoading = true;
+                        } else {
+                            noLoads.push(modId);
+                            removeScript(modId);
+                        }
+                    } else if (!mod.inited && mod.fetched && map.isDefine) {
+                        stillLoading = true;
+                        if (!map.prefix) {
+                            //No reason to keep looking for unfinished
+                            //loading. If the only stillLoading is a
+                            //plugin resource though, keep going,
+                            //because it may be that a plugin resource
+                            //is waiting on a non-plugin cycle.
+                            return (needCycleCheck = false);
+                        }
+                    }
+                }
+            });
+
+            if (expired && noLoads.length) {
+                //If wait time expired, throw error of unloaded modules.
+                err = makeError('timeout', 'Load timeout for modules: ' + noLoads, null, noLoads);
+                err.contextName = context.contextName;
+                return onError(err);
+            }
+
+            //Not expired, check for a cycle.
+            if (needCycleCheck) {
+                each(reqCalls, function (mod) {
+                    breakCycle(mod, {}, {});
+                });
+            }
+
+            //If still waiting on loads, and the waiting load is something
+            //other than a plugin resource, or there are still outstanding
+            //scripts, then just try back later.
+            if ((!expired || usingPathFallback) && stillLoading) {
+                //Something is still waiting to load. Wait for it, but only
+                //if a timeout is not already in effect.
+                if ((isBrowser || isWebWorker) && !checkLoadedTimeoutId) {
+                    checkLoadedTimeoutId = setTimeout(function () {
+                        checkLoadedTimeoutId = 0;
+                        checkLoaded();
+                    }, 50);
+                }
+            }
+
+            inCheckLoaded = false;
+        }
+
+        Module = function (map) {
+            this.events = getOwn(undefEvents, map.id) || {};
+            this.map = map;
+            this.shim = getOwn(config.shim, map.id);
+            this.depExports = [];
+            this.depMaps = [];
+            this.depMatched = [];
+            this.pluginMaps = {};
+            this.depCount = 0;
+
+            /* this.exports this.factory
+               this.depMaps = [],
+               this.enabled, this.fetched
+            */
+        };
+
+        Module.prototype = {
+            init: function (depMaps, factory, errback, options) {
+                options = options || {};
+
+                //Do not do more inits if already done. Can happen if there
+                //are multiple define calls for the same module. That is not
+                //a normal, common case, but it is also not unexpected.
+                if (this.inited) {
+                    return;
+                }
+
+                this.factory = factory;
+
+                if (errback) {
+                    //Register for errors on this module.
+                    this.on('error', errback);
+                } else if (this.events.error) {
+                    //If no errback already, but there are error listeners
+                    //on this module, set up an errback to pass to the deps.
+                    errback = bind(this, function (err) {
+                        this.emit('error', err);
+                    });
+                }
+
+                //Do a copy of the dependency array, so that
+                //source inputs are not modified. For example
+                //"shim" deps are passed in here directly, and
+                //doing a direct modification of the depMaps array
+                //would affect that config.
+                this.depMaps = depMaps && depMaps.slice(0);
+
+                this.errback = errback;
+
+                //Indicate this module has be initialized
+                this.inited = true;
+
+                this.ignore = options.ignore;
+
+                //Could have option to init this module in enabled mode,
+                //or could have been previously marked as enabled. However,
+                //the dependencies are not known until init is called. So
+                //if enabled previously, now trigger dependencies as enabled.
+                if (options.enabled || this.enabled) {
+                    //Enable this module and dependencies.
+                    //Will call this.check()
+                    this.enable();
+                } else {
+                    this.check();
+                }
+            },
+
+            defineDep: function (i, depExports) {
+                //Because of cycles, defined callback for a given
+                //export can be called more than once.
+                if (!this.depMatched[i]) {
+                    this.depMatched[i] = true;
+                    this.depCount -= 1;
+                    this.depExports[i] = depExports;
+                }
+            },
+
+            fetch: function () {
+                if (this.fetched) {
+                    return;
+                }
+                this.fetched = true;
+
+                context.startTime = (new Date()).getTime();
+
+                var map = this.map;
+
+                //If the manager is for a plugin managed resource,
+                //ask the plugin to load it now.
+                if (this.shim) {
+                    context.makeRequire(this.map, {
+                        enableBuildCallback: true
+                    })(this.shim.deps || [], bind(this, function () {
+                        return map.prefix ? this.callPlugin() : this.load();
+                    }));
+                } else {
+                    //Regular dependency.
+                    return map.prefix ? this.callPlugin() : this.load();
+                }
+            },
+
+            load: function () {
+                var url = this.map.url;
+
+                //Regular dependency.
+                if (!urlFetched[url]) {
+                    urlFetched[url] = true;
+                    context.load(this.map.id, url);
+                }
+            },
+
+            /**
+             * Checks if the module is ready to define itself, and if so,
+             * define it.
+             */
+            check: function () {
+                if (!this.enabled || this.enabling) {
+                    return;
+                }
+
+                var err, cjsModule,
+                    id = this.map.id,
+                    depExports = this.depExports,
+                    exports = this.exports,
+                    factory = this.factory;
+
+                if (!this.inited) {
+                    this.fetch();
+                } else if (this.error) {
+                    this.emit('error', this.error);
+                } else if (!this.defining) {
+                    //The factory could trigger another require call
+                    //that would result in checking this module to
+                    //define itself again. If already in the process
+                    //of doing that, skip this work.
+                    this.defining = true;
+
+                    if (this.depCount < 1 && !this.defined) {
+                        if (isFunction(factory)) {
+                            //If there is an error listener, favor passing
+                            //to that instead of throwing an error. However,
+                            //only do it for define()'d  modules. require
+                            //errbacks should not be called for failures in
+                            //their callbacks (#699). However if a global
+                            //onError is set, use that.
+                            if ((this.events.error && this.map.isDefine) ||
+                                req.onError !== defaultOnError) {
+                                try {
+                                    exports = context.execCb(id, factory, depExports, exports);
+                                } catch (e) {
+                                    err = e;
+                                }
+                            } else {
+                                exports = context.execCb(id, factory, depExports, exports);
+                            }
+
+                            // Favor return value over exports. If node/cjs in play,
+                            // then will not have a return value anyway. Favor
+                            // module.exports assignment over exports object.
+                            if (this.map.isDefine && exports === undefined) {
+                                cjsModule = this.module;
+                                if (cjsModule) {
+                                    exports = cjsModule.exports;
+                                } else if (this.usingExports) {
+                                    //exports already set the defined value.
+                                    exports = this.exports;
+                                }
+                            }
+
+                            if (err) {
+                                err.requireMap = this.map;
+                                err.requireModules = this.map.isDefine ? [this.map.id] : null;
+                                err.requireType = this.map.isDefine ? 'define' : 'require';
+                                return onError((this.error = err));
+                            }
+
+                        } else {
+                            //Just a literal value
+                            exports = factory;
+                        }
+
+                        this.exports = exports;
+
+                        if (this.map.isDefine && !this.ignore) {
+                            defined[id] = exports;
+
+                            if (req.onResourceLoad) {
+                                req.onResourceLoad(context, this.map, this.depMaps);
+                            }
+                        }
+
+                        //Clean up
+                        cleanRegistry(id);
+
+                        this.defined = true;
+                    }
+
+                    //Finished the define stage. Allow calling check again
+                    //to allow define notifications below in the case of a
+                    //cycle.
+                    this.defining = false;
+
+                    if (this.defined && !this.defineEmitted) {
+                        this.defineEmitted = true;
+                        this.emit('defined', this.exports);
+                        this.defineEmitComplete = true;
+                    }
+
+                }
+            },
+
+            callPlugin: function () {
+                var map = this.map,
+                    id = map.id,
+                    //Map already normalized the prefix.
+                    pluginMap = makeModuleMap(map.prefix);
+
+                //Mark this as a dependency for this plugin, so it
+                //can be traced for cycles.
+                this.depMaps.push(pluginMap);
+
+                on(pluginMap, 'defined', bind(this, function (plugin) {
+                    var load, normalizedMap, normalizedMod,
+                        bundleId = getOwn(bundlesMap, this.map.id),
+                        name = this.map.name,
+                        parentName = this.map.parentMap ? this.map.parentMap.name : null,
+                        localRequire = context.makeRequire(map.parentMap, {
+                            enableBuildCallback: true
+                        });
+
+                    //If current map is not normalized, wait for that
+                    //normalized name to load instead of continuing.
+                    if (this.map.unnormalized) {
+                        //Normalize the ID if the plugin allows it.
+                        if (plugin.normalize) {
+                            name = plugin.normalize(name, function (name) {
+                                return normalize(name, parentName, true);
+                            }) || '';
+                        }
+
+                        //prefix and name should already be normalized, no need
+                        //for applying map config again either.
+                        normalizedMap = makeModuleMap(map.prefix + '!' + name,
+                                                      this.map.parentMap);
+                        on(normalizedMap,
+                            'defined', bind(this, function (value) {
+                                this.init([], function () { return value; }, null, {
+                                    enabled: true,
+                                    ignore: true
+                                });
+                            }));
+
+                        normalizedMod = getOwn(registry, normalizedMap.id);
+                        if (normalizedMod) {
+                            //Mark this as a dependency for this plugin, so it
+                            //can be traced for cycles.
+                            this.depMaps.push(normalizedMap);
+
+                            if (this.events.error) {
+                                normalizedMod.on('error', bind(this, function (err) {
+                                    this.emit('error', err);
+                                }));
+                            }
+                            normalizedMod.enable();
+                        }
+
+                        return;
+                    }
+
+                    //If a paths config, then just load that file instead to
+                    //resolve the plugin, as it is built into that paths layer.
+                    if (bundleId) {
+                        this.map.url = context.nameToUrl(bundleId);
+                        this.load();
+                        return;
+                    }
+
+                    load = bind(this, function (value) {
+                        this.init([], function () { return value; }, null, {
+                            enabled: true
+                        });
+                    });
+
+                    load.error = bind(this, function (err) {
+                        this.inited = true;
+                        this.error = err;
+                        err.requireModules = [id];
+
+                        //Remove temp unnormalized modules for this module,
+                        //since they will never be resolved otherwise now.
+                        eachProp(registry, function (mod) {
+                            if (mod.map.id.indexOf(id + '_unnormalized') === 0) {
+                                cleanRegistry(mod.map.id);
+                            }
+                        });
+
+                        onError(err);
+                    });
+
+                    //Allow plugins to load other code without having to know the
+                    //context or how to 'complete' the load.
+                    load.fromText = bind(this, function (text, textAlt) {
+                        /*jslint evil: true */
+                        var moduleName = map.name,
+                            moduleMap = makeModuleMap(moduleName),
+                            hasInteractive = useInteractive;
+
+                        //As of 2.1.0, support just passing the text, to reinforce
+                        //fromText only being called once per resource. Still
+                        //support old style of passing moduleName but discard
+                        //that moduleName in favor of the internal ref.
+                        if (textAlt) {
+                            text = textAlt;
+                        }
+
+                        //Turn off interactive script matching for IE for any define
+                        //calls in the text, then turn it back on at the end.
+                        if (hasInteractive) {
+                            useInteractive = false;
+                        }
+
+                        //Prime the system by creating a module instance for
+                        //it.
+                        getModule(moduleMap);
+
+                        //Transfer any config to this other module.
+                        if (hasProp(config.config, id)) {
+                            config.config[moduleName] = config.config[id];
+                        }
+
+                        try {
+                            req.exec(text);
+                        } catch (e) {
+                            return onError(makeError('fromtexteval',
+                                             'fromText eval for ' + id +
+                                            ' failed: ' + e,
+                                             e,
+                                             [id]));
+                        }
+
+                        if (hasInteractive) {
+                            useInteractive = true;
+                        }
+
+                        //Mark this as a dependency for the plugin
+                        //resource
+                        this.depMaps.push(moduleMap);
+
+                        //Support anonymous modules.
+                        context.completeLoad(moduleName);
+
+                        //Bind the value of that module to the value for this
+                        //resource ID.
+                        localRequire([moduleName], load);
+                    });
+
+                    //Use parentName here since the plugin's name is not reliable,
+                    //could be some weird string with no path that actually wants to
+                    //reference the parentName's path.
+                    plugin.load(map.name, localRequire, load, config);
+                }));
+
+                context.enable(pluginMap, this);
+                this.pluginMaps[pluginMap.id] = pluginMap;
+            },
+
+            enable: function () {
+                enabledRegistry[this.map.id] = this;
+                this.enabled = true;
+
+                //Set flag mentioning that the module is enabling,
+                //so that immediate calls to the defined callbacks
+                //for dependencies do not trigger inadvertent load
+                //with the depCount still being zero.
+                this.enabling = true;
+
+                //Enable each dependency
+                each(this.depMaps, bind(this, function (depMap, i) {
+                    var id, mod, handler;
+
+                    if (typeof depMap === 'string') {
+                        //Dependency needs to be converted to a depMap
+                        //and wired up to this module.
+                        depMap = makeModuleMap(depMap,
+                                               (this.map.isDefine ? this.map : this.map.parentMap),
+                                               false,
+                                               !this.skipMap);
+                        this.depMaps[i] = depMap;
+
+                        handler = getOwn(handlers, depMap.id);
+
+                        if (handler) {
+                            this.depExports[i] = handler(this);
+                            return;
+                        }
+
+                        this.depCount += 1;
+
+                        on(depMap, 'defined', bind(this, function (depExports) {
+                            this.defineDep(i, depExports);
+                            this.check();
+                        }));
+
+                        if (this.errback) {
+                            on(depMap, 'error', bind(this, this.errback));
+                        }
+                    }
+
+                    id = depMap.id;
+                    mod = registry[id];
+
+                    //Skip special modules like 'require', 'exports', 'module'
+                    //Also, don't call enable if it is already enabled,
+                    //important in circular dependency cases.
+                    if (!hasProp(handlers, id) && mod && !mod.enabled) {
+                        context.enable(depMap, this);
+                    }
+                }));
+
+                //Enable each plugin that is used in
+                //a dependency
+                eachProp(this.pluginMaps, bind(this, function (pluginMap) {
+                    var mod = getOwn(registry, pluginMap.id);
+                    if (mod && !mod.enabled) {
+                        context.enable(pluginMap, this);
+                    }
+                }));
+
+                this.enabling = false;
+
+                this.check();
+            },
+
+            on: function (name, cb) {
+                var cbs = this.events[name];
+                if (!cbs) {
+                    cbs = this.events[name] = [];
+                }
+                cbs.push(cb);
+            },
+
+            emit: function (name, evt) {
+                each(this.events[name], function (cb) {
+                    cb(evt);
+                });
+                if (name === 'error') {
+                    //Now that the error handler was triggered, remove
+                    //the listeners, since this broken Module instance
+                    //can stay around for a while in the registry.
+                    delete this.events[name];
+                }
+            }
+        };
+
+        function callGetModule(args) {
+            //Skip modules already defined.
+            if (!hasProp(defined, args[0])) {
+                getModule(makeModuleMap(args[0], null, true)).init(args[1], args[2]);
+            }
+        }
+
+        function removeListener(node, func, name, ieName) {
+            //Favor detachEvent because of IE9
+            //issue, see attachEvent/addEventListener comment elsewhere
+            //in this file.
+            if (node.detachEvent && !isOpera) {
+                //Probably IE. If not it will throw an error, which will be
+                //useful to know.
+                if (ieName) {
+                    node.detachEvent(ieName, func);
+                }
+            } else {
+                node.removeEventListener(name, func, false);
+            }
+        }
+
+        /**
+         * Given an event from a script node, get the requirejs info from it,
+         * and then removes the event listeners on the node.
+         * @param {Event} evt
+         * @returns {Object}
+         */
+        function getScriptData(evt) {
+            //Using currentTarget instead of target for Firefox 2.0's sake. Not
+            //all old browsers will be supported, but this one was easy enough
+            //to support and still makes sense.
+            var node = evt.currentTarget || evt.srcElement;
+
+            //Remove the listeners once here.
+            removeListener(node, context.onScriptLoad, 'load', 'onreadystatechange');
+            removeListener(node, context.onScriptError, 'error');
+
+            return {
+                node: node,
+                id: node && node.getAttribute('data-requiremodule')
+            };
+        }
+
+        function intakeDefines() {
+            var args;
+
+            //Any defined modules in the global queue, intake them now.
+            takeGlobalQueue();
+
+            //Make sure any remaining defQueue items get properly processed.
+            while (defQueue.length) {
+                args = defQueue.shift();
+                if (args[0] === null) {
+                    return onError(makeError('mismatch', 'Mismatched anonymous define() module: ' + args[args.length - 1]));
+                } else {
+                    //args are id, deps, factory. Should be normalized by the
+                    //define() function.
+                    callGetModule(args);
+                }
+            }
+        }
+
+        context = {
+            config: config,
+            contextName: contextName,
+            registry: registry,
+            defined: defined,
+            urlFetched: urlFetched,
+            defQueue: defQueue,
+            Module: Module,
+            makeModuleMap: makeModuleMap,
+            nextTick: req.nextTick,
+            onError: onError,
+
+            /**
+             * Set a configuration for the context.
+             * @param {Object} cfg config object to integrate.
+             */
+            configure: function (cfg) {
+                //Make sure the baseUrl ends in a slash.
+                if (cfg.baseUrl) {
+                    if (cfg.baseUrl.charAt(cfg.baseUrl.length - 1) !== '/') {
+                        cfg.baseUrl += '/';
+                    }
+                }
+
+                //Save off the paths since they require special processing,
+                //they are additive.
+                var shim = config.shim,
+                    objs = {
+                        paths: true,
+                        bundles: true,
+                        config: true,
+                        map: true
+                    };
+
+                eachProp(cfg, function (value, prop) {
+                    if (objs[prop]) {
+                        if (!config[prop]) {
+                            config[prop] = {};
+                        }
+                        mixin(config[prop], value, true, true);
+                    } else {
+                        config[prop] = value;
+                    }
+                });
+
+                //Reverse map the bundles
+                if (cfg.bundles) {
+                    eachProp(cfg.bundles, function (value, prop) {
+                        each(value, function (v) {
+                            if (v !== prop) {
+                                bundlesMap[v] = prop;
+                            }
+                        });
+                    });
+                }
+
+                //Merge shim
+                if (cfg.shim) {
+                    eachProp(cfg.shim, function (value, id) {
+                        //Normalize the structure
+                        if (isArray(value)) {
+                            value = {
+                                deps: value
+                            };
+                        }
+                        if ((value.exports || value.init) && !value.exportsFn) {
+                            value.exportsFn = context.makeShimExports(value);
+                        }
+                        shim[id] = value;
+                    });
+                    config.shim = shim;
+                }
+
+                //Adjust packages if necessary.
+                if (cfg.packages) {
+                    each(cfg.packages, function (pkgObj) {
+                        var location, name;
+
+                        pkgObj = typeof pkgObj === 'string' ? { name: pkgObj } : pkgObj;
+
+                        name = pkgObj.name;
+                        location = pkgObj.location;
+                        if (location) {
+                            config.paths[name] = pkgObj.location;
+                        }
+
+                        //Save pointer to main module ID for pkg name.
+                        //Remove leading dot in main, so main paths are normalized,
+                        //and remove any trailing .js, since different package
+                        //envs have different conventions: some use a module name,
+                        //some use a file name.
+                        config.pkgs[name] = pkgObj.name + '/' + (pkgObj.main || 'main')
+                                     .replace(currDirRegExp, '')
+                                     .replace(jsSuffixRegExp, '');
+                    });
+                }
+
+                //If there are any "waiting to execute" modules in the registry,
+                //update the maps for them, since their info, like URLs to load,
+                //may have changed.
+                eachProp(registry, function (mod, id) {
+                    //If module already has init called, since it is too
+                    //late to modify them, and ignore unnormalized ones
+                    //since they are transient.
+                    if (!mod.inited && !mod.map.unnormalized) {
+                        mod.map = makeModuleMap(id);
+                    }
+                });
+
+                //If a deps array or a config callback is specified, then call
+                //require with those args. This is useful when require is defined as a
+                //config object before require.js is loaded.
+                if (cfg.deps || cfg.callback) {
+                    context.require(cfg.deps || [], cfg.callback);
+                }
+            },
+
+            makeShimExports: function (value) {
+                function fn() {
+                    var ret;
+                    if (value.init) {
+                        ret = value.init.apply(global, arguments);
+                    }
+                    return ret || (value.exports && getGlobal(value.exports));
+                }
+                return fn;
+            },
+
+            makeRequire: function (relMap, options) {
+                options = options || {};
+
+                function localRequire(deps, callback, errback) {
+                    var id, map, requireMod;
+
+                    if (options.enableBuildCallback && callback && isFunction(callback)) {
+                        callback.__requireJsBuild = true;
+                    }
+
+                    if (typeof deps === 'string') {
+                        if (isFunction(callback)) {
+                            //Invalid call
+                            return onError(makeError('requireargs', 'Invalid require call'), errback);
+                        }
+
+                        //If require|exports|module are requested, get the
+                        //value for them from the special handlers. Caveat:
+                        //this only works while module is being defined.
+                        if (relMap && hasProp(handlers, deps)) {
+                            return handlers[deps](registry[relMap.id]);
+                        }
+
+                        //Synchronous access to one module. If require.get is
+                        //available (as in the Node adapter), prefer that.
+                        if (req.get) {
+                            return req.get(context, deps, relMap, localRequire);
+                        }
+
+                        //Normalize module name, if it contains . or ..
+                        map = makeModuleMap(deps, relMap, false, true);
+                        id = map.id;
+
+                        if (!hasProp(defined, id)) {
+                            return onError(makeError('notloaded', 'Module name "' +
+                                        id +
+                                        '" has not been loaded yet for context: ' +
+                                        contextName +
+                                        (relMap ? '' : '. Use require([])')));
+                        }
+                        return defined[id];
+                    }
+
+                    //Grab defines waiting in the global queue.
+                    intakeDefines();
+
+                    //Mark all the dependencies as needing to be loaded.
+                    context.nextTick(function () {
+                        //Some defines could have been added since the
+                        //require call, collect them.
+                        intakeDefines();
+
+                        requireMod = getModule(makeModuleMap(null, relMap));
+
+                        //Store if map config should be applied to this require
+                        //call for dependencies.
+                        requireMod.skipMap = options.skipMap;
+
+                        requireMod.init(deps, callback, errback, {
+                            enabled: true
+                        });
+
+                        checkLoaded();
+                    });
+
+                    return localRequire;
+                }
+
+                mixin(localRequire, {
+                    isBrowser: isBrowser,
+
+                    /**
+                     * Converts a module name + .extension into an URL path.
+                     * *Requires* the use of a module name. It does not support using
+                     * plain URLs like nameToUrl.
+                     */
+                    toUrl: function (moduleNamePlusExt) {
+                        var ext,
+                            index = moduleNamePlusExt.lastIndexOf('.'),
+                            segment = moduleNamePlusExt.split('/')[0],
+                            isRelative = segment === '.' || segment === '..';
+
+                        //Have a file extension alias, and it is not the
+                        //dots from a relative path.
+                        if (index !== -1 && (!isRelative || index > 1)) {
+                            ext = moduleNamePlusExt.substring(index, moduleNamePlusExt.length);
+                            moduleNamePlusExt = moduleNamePlusExt.substring(0, index);
+                        }
+
+                        return context.nameToUrl(normalize(moduleNamePlusExt,
+                                                relMap && relMap.id, true), ext,  true);
+                    },
+
+                    defined: function (id) {
+                        return hasProp(defined, makeModuleMap(id, relMap, false, true).id);
+                    },
+
+                    specified: function (id) {
+                        id = makeModuleMap(id, relMap, false, true).id;
+                        return hasProp(defined, id) || hasProp(registry, id);
+                    }
+                });
+
+                //Only allow undef on top level require calls
+                if (!relMap) {
+                    localRequire.undef = function (id) {
+                        //Bind any waiting define() calls to this context,
+                        //fix for #408
+                        takeGlobalQueue();
+
+                        var map = makeModuleMap(id, relMap, true),
+                            mod = getOwn(registry, id);
+
+                        removeScript(id);
+
+                        delete defined[id];
+                        delete urlFetched[map.url];
+                        delete undefEvents[id];
+
+                        //Clean queued defines too. Go backwards
+                        //in array so that the splices do not
+                        //mess up the iteration.
+                        eachReverse(defQueue, function(args, i) {
+                            if(args[0] === id) {
+                                defQueue.splice(i, 1);
+                            }
+                        });
+
+                        if (mod) {
+                            //Hold on to listeners in case the
+                            //module will be attempted to be reloaded
+                            //using a different config.
+                            if (mod.events.defined) {
+                                undefEvents[id] = mod.events;
+                            }
+
+                            cleanRegistry(id);
+                        }
+                    };
+                }
+
+                return localRequire;
+            },
+
+            /**
+             * Called to enable a module if it is still in the registry
+             * awaiting enablement. A second arg, parent, the parent module,
+             * is passed in for context, when this method is overridden by
+             * the optimizer. Not shown here to keep code compact.
+             */
+            enable: function (depMap) {
+                var mod = getOwn(registry, depMap.id);
+                if (mod) {
+                    getModule(depMap).enable();
+                }
+            },
+
+            /**
+             * Internal method used by environment adapters to complete a load event.
+             * A load event could be a script load or just a load pass from a synchronous
+             * load call.
+             * @param {String} moduleName the name of the module to potentially complete.
+             */
+            completeLoad: function (moduleName) {
+                var found, args, mod,
+                    shim = getOwn(config.shim, moduleName) || {},
+                    shExports = shim.exports;
+
+                takeGlobalQueue();
+
+                while (defQueue.length) {
+                    args = defQueue.shift();
+                    if (args[0] === null) {
+                        args[0] = moduleName;
+                        //If already found an anonymous module and bound it
+                        //to this name, then this is some other anon module
+                        //waiting for its completeLoad to fire.
+                        if (found) {
+                            break;
+                        }
+                        found = true;
+                    } else if (args[0] === moduleName) {
+                        //Found matching define call for this script!
+                        found = true;
+                    }
+
+                    callGetModule(args);
+                }
+
+                //Do this after the cycle of callGetModule in case the result
+                //of those calls/init calls changes the registry.
+                mod = getOwn(registry, moduleName);
+
+                if (!found && !hasProp(defined, moduleName) && mod && !mod.inited) {
+                    if (config.enforceDefine && (!shExports || !getGlobal(shExports))) {
+                        if (hasPathFallback(moduleName)) {
+                            return;
+                        } else {
+                            return onError(makeError('nodefine',
+                                             'No define call for ' + moduleName,
+                                             null,
+                                             [moduleName]));
+                        }
+                    } else {
+                        //A script that does not call define(), so just simulate
+                        //the call for it.
+                        callGetModule([moduleName, (shim.deps || []), shim.exportsFn]);
+                    }
+                }
+
+                checkLoaded();
+            },
+
+            /**
+             * Converts a module name to a file path. Supports cases where
+             * moduleName may actually be just an URL.
+             * Note that it **does not** call normalize on the moduleName,
+             * it is assumed to have already been normalized. This is an
+             * internal API, not a public one. Use toUrl for the public API.
+             */
+            nameToUrl: function (moduleName, ext, skipExt) {
+                var paths, syms, i, parentModule, url,
+                    parentPath, bundleId,
+                    pkgMain = getOwn(config.pkgs, moduleName);
+
+                if (pkgMain) {
+                    moduleName = pkgMain;
+                }
+
+                bundleId = getOwn(bundlesMap, moduleName);
+
+                if (bundleId) {
+                    return context.nameToUrl(bundleId, ext, skipExt);
+                }
+
+                //If a colon is in the URL, it indicates a protocol is used and it is just
+                //an URL to a file, or if it starts with a slash, contains a query arg (i.e. ?)
+                //or ends with .js, then assume the user meant to use an url and not a module id.
+                //The slash is important for protocol-less URLs as well as full paths.
+                if (req.jsExtRegExp.test(moduleName)) {
+                    //Just a plain path, not module name lookup, so just return it.
+                    //Add extension if it is included. This is a bit wonky, only non-.js things pass
+                    //an extension, this method probably needs to be reworked.
+                    url = moduleName + (ext || '');
+                } else {
+                    //A module that needs to be converted to a path.
+                    paths = config.paths;
+
+                    syms = moduleName.split('/');
+                    //For each module name segment, see if there is a path
+                    //registered for it. Start with most specific name
+                    //and work up from it.
+                    for (i = syms.length; i > 0; i -= 1) {
+                        parentModule = syms.slice(0, i).join('/');
+
+                        parentPath = getOwn(paths, parentModule);
+                        if (parentPath) {
+                            //If an array, it means there are a few choices,
+                            //Choose the one that is desired
+                            if (isArray(parentPath)) {
+                                parentPath = parentPath[0];
+                            }
+                            syms.splice(0, i, parentPath);
+                            break;
+                        }
+                    }
+
+                    //Join the path parts together, then figure out if baseUrl is needed.
+                    url = syms.join('/');
+                    url += (ext || (/^data\:|\?/.test(url) || skipExt ? '' : '.js'));
+                    url = (url.charAt(0) === '/' || url.match(/^[\w\+\.\-]+:/) ? '' : config.baseUrl) + url;
+                }
+
+                return config.urlArgs ? url +
+                                        ((url.indexOf('?') === -1 ? '?' : '&') +
+                                         config.urlArgs) : url;
+            },
+
+            //Delegates to req.load. Broken out as a separate function to
+            //allow overriding in the optimizer.
+            load: function (id, url) {
+                req.load(context, id, url);
+            },
+
+            /**
+             * Executes a module callback function. Broken out as a separate function
+             * solely to allow the build system to sequence the files in the built
+             * layer in the right sequence.
+             *
+             * @private
+             */
+            execCb: function (name, callback, args, exports) {
+                return callback.apply(exports, args);
+            },
+
+            /**
+             * callback for script loads, used to check status of loading.
+             *
+             * @param {Event} evt the event from the browser for the script
+             * that was loaded.
+             */
+            onScriptLoad: function (evt) {
+                //Using currentTarget instead of target for Firefox 2.0's sake. Not
+                //all old browsers will be supported, but this one was easy enough
+                //to support and still makes sense.
+                if (evt.type === 'load' ||
+                        (readyRegExp.test((evt.currentTarget || evt.srcElement).readyState))) {
+                    //Reset interactive script so a script node is not held onto for
+                    //to long.
+                    interactiveScript = null;
+
+                    //Pull out the name of the module and the context.
+                    var data = getScriptData(evt);
+                    context.completeLoad(data.id);
+                }
+            },
+
+            /**
+             * Callback for script errors.
+             */
+            onScriptError: function (evt) {
+                var data = getScriptData(evt);
+                if (!hasPathFallback(data.id)) {
+                    return onError(makeError('scripterror', 'Script error for: ' + data.id, evt, [data.id]));
+                }
+            }
+        };
+
+        context.require = context.makeRequire();
+        return context;
+    }
+
+    /**
+     * Main entry point.
+     *
+     * If the only argument to require is a string, then the module that
+     * is represented by that string is fetched for the appropriate context.
+     *
+     * If the first argument is an array, then it will be treated as an array
+     * of dependency string names to fetch. An optional function callback can
+     * be specified to execute when all of those dependencies are available.
+     *
+     * Make a local req variable to help Caja compliance (it assumes things
+     * on a require that are not standardized), and to give a short
+     * name for minification/local scope use.
+     */
+    req = requirejs = function (deps, callback, errback, optional) {
+
+        //Find the right context, use default
+        var context, config,
+            contextName = defContextName;
+
+        // Determine if have config object in the call.
+        if (!isArray(deps) && typeof deps !== 'string') {
+            // deps is a config object
+            config = deps;
+            if (isArray(callback)) {
+                // Adjust args if there are dependencies
+                deps = callback;
+                callback = errback;
+                errback = optional;
+            } else {
+                deps = [];
+            }
+        }
+
+        if (config && config.context) {
+            contextName = config.context;
+        }
+
+        context = getOwn(contexts, contextName);
+        if (!context) {
+            context = contexts[contextName] = req.s.newContext(contextName);
+        }
+
+        if (config) {
+            context.configure(config);
+        }
+
+        return context.require(deps, callback, errback);
+    };
+
+    /**
+     * Support require.config() to make it easier to cooperate with other
+     * AMD loaders on globally agreed names.
+     */
+    req.config = function (config) {
+        return req(config);
+    };
+
+    /**
+     * Execute something after the current tick
+     * of the event loop. Override for other envs
+     * that have a better solution than setTimeout.
+     * @param  {Function} fn function to execute later.
+     */
+    req.nextTick = typeof setTimeout !== 'undefined' ? function (fn) {
+        setTimeout(fn, 4);
+    } : function (fn) { fn(); };
+
+    /**
+     * Export require as a global, but only if it does not already exist.
+     */
+    if (!require) {
+        require = req;
+    }
+
+    req.version = version;
+
+    //Used to filter out dependencies that are already paths.
+    req.jsExtRegExp = /^\/|:|\?|\.js$/;
+    req.isBrowser = isBrowser;
+    s = req.s = {
+        contexts: contexts,
+        newContext: newContext
+    };
+
+    //Create default context.
+    req({});
+
+    //Exports some context-sensitive methods on global require.
+    each([
+        'toUrl',
+        'undef',
+        'defined',
+        'specified'
+    ], function (prop) {
+        //Reference from contexts instead of early binding to default context,
+        //so that during builds, the latest instance of the default context
+        //with its config gets used.
+        req[prop] = function () {
+            var ctx = contexts[defContextName];
+            return ctx.require[prop].apply(ctx, arguments);
+        };
+    });
+
+    if (isBrowser) {
+        head = s.head = document.getElementsByTagName('head')[0];
+        //If BASE tag is in play, using appendChild is a problem for IE6.
+        //When that browser dies, this can be removed. Details in this jQuery bug:
+        //http://dev.jquery.com/ticket/2709
+        baseElement = document.getElementsByTagName('base')[0];
+        if (baseElement) {
+            head = s.head = baseElement.parentNode;
+        }
+    }
+
+    /**
+     * Any errors that require explicitly generates will be passed to this
+     * function. Intercept/override it if you want custom error handling.
+     * @param {Error} err the error object.
+     */
+    req.onError = defaultOnError;
+
+    /**
+     * Creates the node for the load command. Only used in browser envs.
+     */
+    req.createNode = function (config, moduleName, url) {
+        var node = config.xhtml ?
+                document.createElementNS('http://www.w3.org/1999/xhtml', 'html:script') :
+                document.createElement('script');
+        node.type = config.scriptType || 'text/javascript';
+        node.charset = 'utf-8';
+        node.async = true;
+        return node;
+    };
+
+    /**
+     * Does the request to load a module for the browser case.
+     * Make this a separate function to allow other environments
+     * to override it.
+     *
+     * @param {Object} context the require context to find state.
+     * @param {String} moduleName the name of the module.
+     * @param {Object} url the URL to the module.
+     */
+    req.load = function (context, moduleName, url) {
+        var config = (context && context.config) || {},
+            node;
+        if (isBrowser) {
+            //In the browser so use a script tag
+            node = req.createNode(config, moduleName, url);
+
+            node.setAttribute('data-requirecontext', context.contextName);
+            node.setAttribute('data-requiremodule', moduleName);
+
+            //Set up load listener. Test attachEvent first because IE9 has
+            //a subtle issue in its addEventListener and script onload firings
+            //that do not match the behavior of all other browsers with
+            //addEventListener support, which fire the onload event for a
+            //script right after the script execution. See:
+            //https://connect.microsoft.com/IE/feedback/details/648057/script-onload-event-is-not-fired-immediately-after-script-execution
+            //UNFORTUNATELY Opera implements attachEvent but does not follow the script
+            //script execution mode.
+            if (node.attachEvent &&
+                    //Check if node.attachEvent is artificially added by custom script or
+                    //natively supported by browser
+                    //read https://github.com/jrburke/requirejs/issues/187
+                    //if we can NOT find [native code] then it must NOT natively supported.
+                    //in IE8, node.attachEvent does not have toString()
+                    //Note the test for "[native code" with no closing brace, see:
+                    //https://github.com/jrburke/requirejs/issues/273
+                    !(node.attachEvent.toString && node.attachEvent.toString().indexOf('[native code') < 0) &&
+                    !isOpera) {
+                //Probably IE. IE (at least 6-8) do not fire
+                //script onload right after executing the script, so
+                //we cannot tie the anonymous define call to a name.
+                //However, IE reports the script as being in 'interactive'
+                //readyState at the time of the define call.
+                useInteractive = true;
+
+                node.attachEvent('onreadystatechange', context.onScriptLoad);
+                //It would be great to add an error handler here to catch
+                //404s in IE9+. However, onreadystatechange will fire before
+                //the error handler, so that does not help. If addEventListener
+                //is used, then IE will fire error before load, but we cannot
+                //use that pathway given the connect.microsoft.com issue
+                //mentioned above about not doing the 'script execute,
+                //then fire the script load event listener before execute
+                //next script' that other browsers do.
+                //Best hope: IE10 fixes the issues,
+                //and then destroys all installs of IE 6-9.
+                //node.attachEvent('onerror', context.onScriptError);
+            } else {
+                node.addEventListener('load', context.onScriptLoad, false);
+                node.addEventListener('error', context.onScriptError, false);
+            }
+            node.src = url;
+
+            //For some cache cases in IE 6-8, the script executes before the end
+            //of the appendChild execution, so to tie an anonymous define
+            //call to the module name (which is stored on the node), hold on
+            //to a reference to this node, but clear after the DOM insertion.
+            currentlyAddingScript = node;
+            if (baseElement) {
+                head.insertBefore(node, baseElement);
+            } else {
+                head.appendChild(node);
+            }
+            currentlyAddingScript = null;
+
+            return node;
+        } else if (isWebWorker) {
+            try {
+                //In a web worker, use importScripts. This is not a very
+                //efficient use of importScripts, importScripts will block until
+                //its script is downloaded and evaluated. However, if web workers
+                //are in play, the expectation that a build has been done so that
+                //only one script needs to be loaded anyway. This may need to be
+                //reevaluated if other use cases become common.
+                importScripts(url);
+
+                //Account for anonymous modules
+                context.completeLoad(moduleName);
+            } catch (e) {
+                context.onError(makeError('importscripts',
+                                'importScripts failed for ' +
+                                    moduleName + ' at ' + url,
+                                e,
+                                [moduleName]));
+            }
+        }
+    };
+
+    function getInteractiveScript() {
+        if (interactiveScript && interactiveScript.readyState === 'interactive') {
+            return interactiveScript;
+        }
+
+        eachReverse(scripts(), function (script) {
+            if (script.readyState === 'interactive') {
+                return (interactiveScript = script);
+            }
+        });
+        return interactiveScript;
+    }
+
+    //Look for a data-main script attribute, which could also adjust the baseUrl.
+    if (isBrowser && !cfg.skipDataMain) {
+        //Figure out baseUrl. Get it from the script tag with require.js in it.
+        eachReverse(scripts(), function (script) {
+            //Set the 'head' where we can append children by
+            //using the script's parent.
+            if (!head) {
+                head = script.parentNode;
+            }
+
+            //Look for a data-main attribute to set main script for the page
+            //to load. If it is there, the path to data main becomes the
+            //baseUrl, if it is not already set.
+            dataMain = script.getAttribute('data-main');
+            if (dataMain) {
+                //Preserve dataMain in case it is a path (i.e. contains '?')
+                mainScript = dataMain;
+
+                //Set final baseUrl if there is not already an explicit one.
+                if (!cfg.baseUrl) {
+                    //Pull off the directory of data-main for use as the
+                    //baseUrl.
+                    src = mainScript.split('/');
+                    mainScript = src.pop();
+                    subPath = src.length ? src.join('/')  + '/' : './';
+
+                    cfg.baseUrl = subPath;
+                }
+
+                //Strip off any trailing .js since mainScript is now
+                //like a module name.
+                mainScript = mainScript.replace(jsSuffixRegExp, '');
+
+                 //If mainScript is still a path, fall back to dataMain
+                if (req.jsExtRegExp.test(mainScript)) {
+                    mainScript = dataMain;
+                }
+
+                //Put the data-main script in the files to load.
+                cfg.deps = cfg.deps ? cfg.deps.concat(mainScript) : [mainScript];
+
+                return true;
+            }
+        });
+    }
+
+    /**
+     * The function that handles definitions of modules. Differs from
+     * require() in that a string for the module should be the first argument,
+     * and the function to execute after dependencies are loaded should
+     * return a value to define the module corresponding to the first argument's
+     * name.
+     */
+    define = function (name, deps, callback) {
+        var node, context;
+
+        //Allow for anonymous modules
+        if (typeof name !== 'string') {
+            //Adjust args appropriately
+            callback = deps;
+            deps = name;
+            name = null;
+        }
+
+        //This module may not have dependencies
+        if (!isArray(deps)) {
+            callback = deps;
+            deps = null;
+        }
+
+        //If no name, and callback is a function, then figure out if it a
+        //CommonJS thing with dependencies.
+        if (!deps && isFunction(callback)) {
+            deps = [];
+            //Remove comments from the callback string,
+            //look for require calls, and pull them into the dependencies,
+            //but only if there are function args.
+            if (callback.length) {
+                callback
+                    .toString()
+                    .replace(commentRegExp, '')
+                    .replace(cjsRequireRegExp, function (match, dep) {
+                        deps.push(dep);
+                    });
+
+                //May be a CommonJS thing even without require calls, but still
+                //could use exports, and module. Avoid doing exports and module
+                //work though if it just needs require.
+                //REQUIRES the function to expect the CommonJS variables in the
+                //order listed below.
+                deps = (callback.length === 1 ? ['require'] : ['require', 'exports', 'module']).concat(deps);
+            }
+        }
+
+        //If in IE 6-8 and hit an anonymous define() call, do the interactive
+        //work.
+        if (useInteractive) {
+            node = currentlyAddingScript || getInteractiveScript();
+            if (node) {
+                if (!name) {
+                    name = node.getAttribute('data-requiremodule');
+                }
+                context = contexts[node.getAttribute('data-requirecontext')];
+            }
+        }
+
+        //Always save off evaluating the def call until the script onload handler.
+        //This allows multiple modules to be in a file without prematurely
+        //tracing dependencies, and allows for anonymous module support,
+        //where the module name is not known until the script onload event
+        //occurs. If no context, use the global queue, and get it processed
+        //in the onscript load callback.
+        (context ? context.defQueue : globalDefQueue).push([name, deps, callback]);
+    };
+
+    define.amd = {
+        jQuery: true
+    };
+
+
+    /**
+     * Executes the text. Normally just uses eval, but can be modified
+     * to use a better, environment-specific call. Only used for transpiling
+     * loader plugins, not for plain JS modules.
+     * @param {String} text the text to execute/evaluate.
+     */
+    req.exec = function (text) {
+        /*jslint evil: true */
+        return eval(text);
+    };
+
+    //Set up with config info.
+    req(cfg);
+}(this));
diff --git a/devtools/client/jsonview/moz.build b/devtools/client/jsonview/moz.build
new file mode 100644
index 0000000000..8d0350ef3f
--- /dev/null
+++ b/devtools/client/jsonview/moz.build
@@ -0,0 +1,24 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+DIRS += ["components", "css", "lib"]
+
+DevToolsModules(
+    "converter-child.js",
+    "Converter.sys.mjs",
+    "json-viewer.js",
+    "Sniffer.sys.mjs",
+    "viewer-config.js",
+)
+
+XPCOM_MANIFESTS += [
+    "components.conf",
+]
+
+BROWSER_CHROME_MANIFESTS += ["test/browser.ini"]
+
+with Files("**"):
+    BUG_COMPONENT = ("DevTools", "JSON Viewer")
diff --git a/devtools/client/jsonview/test/array_json.json b/devtools/client/jsonview/test/array_json.json
new file mode 100644
index 0000000000..a53a19fa70
--- /dev/null
+++ b/devtools/client/jsonview/test/array_json.json
@@ -0,0 +1 @@
+[{ "name": "jan" }, { "name": "honza" }, { "name": "odvarko" }]
diff --git a/devtools/client/jsonview/test/array_json.json^headers^ b/devtools/client/jsonview/test/array_json.json^headers^
new file mode 100644
index 0000000000..6010bfd188
--- /dev/null
+++ b/devtools/client/jsonview/test/array_json.json^headers^
@@ -0,0 +1 @@
+Content-Type: application/json; charset=utf-8
diff --git a/devtools/client/jsonview/test/browser.ini b/devtools/client/jsonview/test/browser.ini
new file mode 100644
index 0000000000..0acb44c6b3
--- /dev/null
+++ b/devtools/client/jsonview/test/browser.ini
@@ -0,0 +1,59 @@
+[DEFAULT]
+tags = devtools
+subsuite = devtools
+support-files =
+  array_json.json
+  array_json.json^headers^
+  csp_json.json
+  csp_json.json^headers^
+  empty.html
+  head.js
+  invalid_json.json
+  invalid_json.json^headers^
+  manifest_json.json
+  manifest_json.json^headers^
+  passthrough-sw.js
+  simple_json.json
+  simple_json.json^headers^
+  valid_json.json
+  valid_json.json^headers^
+  !/devtools/client/framework/test/head.js
+  !/devtools/client/shared/test/shared-head.js
+  !/devtools/client/shared/test/telemetry-test-helpers.js
+
+[browser_json_refresh.js]
+[browser_jsonview_bug_1380828.js]
+[browser_jsonview_chunked_json.js]
+skip-if = http3 # Bug 1829298
+support-files =
+  chunked_json.sjs
+[browser_jsonview_content_type.js]
+[browser_jsonview_copy_headers.js]
+[browser_jsonview_copy_json.js]
+[browser_jsonview_copy_rawdata.js]
+[browser_jsonview_csp_json.js]
+[browser_jsonview_data_blocking.js]
+[browser_jsonview_empty_object.js]
+[browser_jsonview_encoding.js]
+[browser_jsonview_filter.js]
+[browser_jsonview_filter_clear.js]
+[browser_jsonview_ignore_charset.js]
+[browser_jsonview_initial_focus.js]
+[browser_jsonview_invalid_json.js]
+[browser_jsonview_manifest.js]
+[browser_jsonview_nojs.js]
+[browser_jsonview_nul.js]
+[browser_jsonview_object-type.js]
+[browser_jsonview_row_selection.js]
+[browser_jsonview_save_json.js]
+skip-if = http3 # Bug 1829298
+support-files =
+  !/toolkit/content/tests/browser/common/mockTransfer.js
+[browser_jsonview_serviceworker.js]
+[browser_jsonview_slash.js]
+[browser_jsonview_theme.js]
+[browser_jsonview_url_linkification.js]
+[browser_jsonview_valid_json.js]
+[browser_jsonview_expand_collapse.js]
+skip-if =
+  os == 'linux' && bits == 64 && !debug # Bug 1794904
diff --git a/devtools/client/jsonview/test/browser_json_refresh.js b/devtools/client/jsonview/test/browser_json_refresh.js
new file mode 100644
index 0000000000..0fbebbae57
--- /dev/null
+++ b/devtools/client/jsonview/test/browser_json_refresh.js
@@ -0,0 +1,97 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const TEST_JSON_FILE = "simple_json.json";
+
+add_task(async function () {
+  info("Test JSON refresh started");
+
+  // generate file:// URI for JSON file and load in new tab
+  const dir = getChromeDir(getResolvedURI(gTestPath));
+  dir.append(TEST_JSON_FILE);
+  dir.normalize();
+  const uri = Services.io.newFileURI(dir);
+  const tab = await addJsonViewTab(uri.spec);
+
+  // perform sanity checks for URI and principals in loadInfo
+  await SpecialPowers.spawn(
+    tab.linkedBrowser,
+    [{ TEST_JSON_FILE }],
+    // eslint-disable-next-line no-shadow
+    async function ({ TEST_JSON_FILE }) {
+      const channel = content.docShell.currentDocumentChannel;
+      const channelURI = channel.URI.spec;
+      ok(
+        channelURI.startsWith("file://") && channelURI.includes(TEST_JSON_FILE),
+        "sanity: correct channel uri"
+      );
+      const contentPolicyType = channel.loadInfo.externalContentPolicyType;
+      is(
+        contentPolicyType,
+        Ci.nsIContentPolicy.TYPE_DOCUMENT,
+        "sanity: correct contentPolicyType"
+      );
+
+      const loadingPrincipal = channel.loadInfo.loadingPrincipal;
+      is(loadingPrincipal, null, "sanity: correct loadingPrincipal");
+      const triggeringPrincipal = channel.loadInfo.triggeringPrincipal;
+      ok(
+        triggeringPrincipal.isSystemPrincipal,
+        "sanity: correct triggeringPrincipal"
+      );
+      const principalToInherit = channel.loadInfo.principalToInherit;
+      ok(
+        principalToInherit.isNullPrincipal,
+        "sanity: correct principalToInherit"
+      );
+      ok(
+        content.document.nodePrincipal.isNullPrincipal,
+        "sanity: correct doc.nodePrincipal"
+      );
+    }
+  );
+
+  // reload the tab
+  await reloadBrowser();
+
+  // check principals in loadInfo are still correct
+  await SpecialPowers.spawn(
+    tab.linkedBrowser,
+    [{ TEST_JSON_FILE }],
+    // eslint-disable-next-line no-shadow
+    async function ({ TEST_JSON_FILE }) {
+      // eslint-disable-line
+      const channel = content.docShell.currentDocumentChannel;
+      const channelURI = channel.URI.spec;
+      ok(
+        channelURI.startsWith("file://") && channelURI.includes(TEST_JSON_FILE),
+        "reloaded: correct channel uri"
+      );
+      const contentPolicyType = channel.loadInfo.externalContentPolicyType;
+      is(
+        contentPolicyType,
+        Ci.nsIContentPolicy.TYPE_DOCUMENT,
+        "reloaded: correct contentPolicyType"
+      );
+
+      const loadingPrincipal = channel.loadInfo.loadingPrincipal;
+      is(loadingPrincipal, null, "reloaded: correct loadingPrincipal");
+      const triggeringPrincipal = channel.loadInfo.triggeringPrincipal;
+      ok(
+        triggeringPrincipal.isSystemPrincipal,
+        "reloaded: correct triggeringPrincipal"
+      );
+      const principalToInherit = channel.loadInfo.principalToInherit;
+      ok(
+        principalToInherit.isNullPrincipal,
+        "reloaded: correct principalToInherit"
+      );
+      ok(
+        content.document.nodePrincipal.isNullPrincipal,
+        "reloaded: correct doc.nodePrincipal"
+      );
+    }
+  );
+});
diff --git a/devtools/client/jsonview/test/browser_jsonview_bug_1380828.js b/devtools/client/jsonview/test/browser_jsonview_bug_1380828.js
new file mode 100644
index 0000000000..6d698e8930
--- /dev/null
+++ b/devtools/client/jsonview/test/browser_jsonview_bug_1380828.js
@@ -0,0 +1,32 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const VALID_JSON_URL = URL_ROOT + "valid_json.json";
+const INVALID_JSON_URL = URL_ROOT + "invalid_json.json";
+const prettyPrintButtonClass = ".textPanelBox .toolbar button.prettyprint";
+
+add_task(async function () {
+  info("Test 'Pretty Print' button disappears on parsing invalid JSON");
+
+  const count = await testPrettyPrintButton(INVALID_JSON_URL);
+  is(count, 0, "There must be no pretty-print button for invalid json");
+});
+
+add_task(async function () {
+  info("Test 'Pretty Print' button is present on parsing valid JSON");
+
+  const count = await testPrettyPrintButton(VALID_JSON_URL);
+  is(count, 1, "There must be pretty-print button for valid json");
+});
+
+async function testPrettyPrintButton(url) {
+  await addJsonViewTab(url);
+
+  await selectJsonViewContentTab("rawdata");
+  info("Switched to Raw Data tab.");
+
+  const count = await getElementCount(prettyPrintButtonClass);
+  return count;
+}
diff --git a/devtools/client/jsonview/test/browser_jsonview_chunked_json.js b/devtools/client/jsonview/test/browser_jsonview_chunked_json.js
new file mode 100644
index 0000000000..56fe611486
--- /dev/null
+++ b/devtools/client/jsonview/test/browser_jsonview_chunked_json.js
@@ -0,0 +1,121 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const TEST_JSON_URL = URL_ROOT_SSL + "chunked_json.sjs";
+
+add_task(async function () {
+  info("Test chunked JSON started");
+
+  await addJsonViewTab(TEST_JSON_URL, {
+    appReadyState: "interactive",
+    docReadyState: "loading",
+  });
+
+  is(
+    await getElementCount(".rawdata.is-active"),
+    1,
+    "The Raw Data tab is selected."
+  );
+
+  // Write some text and check that it is displayed.
+  await write("[");
+  await checkText();
+
+  // Repeat just in case.
+  await write("1,");
+  await checkText();
+
+  is(
+    await getElementCount("button.prettyprint"),
+    0,
+    "There is no pretty print button during load"
+  );
+
+  await selectJsonViewContentTab("json");
+  is(
+    await getElementText(".jsonPanelBox > .panelContent"),
+    "",
+    "There is no JSON tree"
+  );
+
+  await selectJsonViewContentTab("headers");
+  ok(
+    await getElementText(".headersPanelBox .netInfoHeadersTable"),
+    "The headers table has been filled."
+  );
+
+  // Write some text without being in Raw Data, then switch tab and check.
+  await write("2");
+  await selectJsonViewContentTab("rawdata");
+  await checkText();
+
+  // Add an array, when counting rows we will ensure it has been expanded automatically.
+  await write(",[3]]");
+  await checkText();
+
+  // Close the connection.
+
+  // When the ready state of the JSON View app changes, it triggers the
+  // custom event "AppReadyStateChange".
+  const appReady = BrowserTestUtils.waitForContentEvent(
+    gBrowser.selectedBrowser,
+    "AppReadyStateChange",
+    true,
+    null,
+    true
+  );
+  await server("close");
+  await appReady;
+
+  is(await getElementCount(".json.is-active"), 1, "The JSON tab is selected.");
+
+  is(
+    await getElementCount(".jsonPanelBox .treeTable .treeRow"),
+    4,
+    "There is a tree with 4 rows."
+  );
+
+  await selectJsonViewContentTab("rawdata");
+  await checkText();
+
+  is(
+    await getElementCount("button.prettyprint"),
+    1,
+    "There is a pretty print button."
+  );
+  await clickJsonNode("button.prettyprint");
+  await checkText(JSON.stringify(JSON.parse(data), null, 2));
+});
+
+let data = " ";
+async function write(text) {
+  data += text;
+  const onJsonViewUpdated = SpecialPowers.spawn(
+    gBrowser.selectedBrowser,
+    [],
+    () => {
+      return new Promise(resolve => {
+        const observer = new content.MutationObserver(() => resolve());
+        observer.observe(content.wrappedJSObject.JSONView.json, {
+          characterData: true,
+        });
+      });
+    }
+  );
+  await server("write", text);
+  await onJsonViewUpdated;
+}
+async function checkText(text = data) {
+  is(await getElementText(".textPanelBox .data"), text, "Got the right text.");
+}
+
+function server(action, value) {
+  return new Promise(resolve => {
+    const xhr = new XMLHttpRequest();
+    xhr.open("GET", TEST_JSON_URL + "?" + action + "=" + value);
+    xhr.addEventListener("load", resolve, { once: true });
+    xhr.send();
+  });
+}
diff --git a/devtools/client/jsonview/test/browser_jsonview_content_type.js b/devtools/client/jsonview/test/browser_jsonview_content_type.js
new file mode 100644
index 0000000000..c3298cc7d9
--- /dev/null
+++ b/devtools/client/jsonview/test/browser_jsonview_content_type.js
@@ -0,0 +1,100 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const mimeSvc = Cc["@mozilla.org/mime;1"].getService(Ci.nsIMIMEService);
+const handlerSvc = Cc["@mozilla.org/uriloader/handler-service;1"].getService(
+  Ci.nsIHandlerService
+);
+
+const contentTypes = {
+  valid: [
+    "application/json",
+    "application/manifest+json",
+    "application/vnd.api+json",
+    "application/hal+json",
+    "application/json+json",
+    "application/whatever+json",
+  ],
+  invalid: [
+    "text/json",
+    "text/hal+json",
+    "application/jsona",
+    "application/whatever+jsona",
+  ],
+};
+
+add_task(async function () {
+  info("Test JSON content types started");
+
+  // Prevent saving files to disk.
+  const useDownloadDir = SpecialPowers.getBoolPref(
+    "browser.download.useDownloadDir"
+  );
+  SpecialPowers.setBoolPref("browser.download.useDownloadDir", false);
+  const { MockFilePicker } = SpecialPowers;
+  MockFilePicker.init(window);
+  MockFilePicker.returnValue = MockFilePicker.returnCancel;
+
+  for (const kind of Object.keys(contentTypes)) {
+    const isValid = kind === "valid";
+    for (const type of contentTypes[kind]) {
+      // Prevent "Open or Save" dialogs, which would make the test fail.
+      const mimeInfo = mimeSvc.getFromTypeAndExtension(type, null);
+      const exists = handlerSvc.exists(mimeInfo);
+      const { alwaysAskBeforeHandling } = mimeInfo;
+      mimeInfo.alwaysAskBeforeHandling = false;
+      handlerSvc.store(mimeInfo);
+
+      await testType(isValid, type);
+      await testType(isValid, type, ";foo=bar+json");
+
+      // Restore old nsIMIMEInfo
+      if (exists) {
+        Object.assign(mimeInfo, { alwaysAskBeforeHandling });
+        handlerSvc.store(mimeInfo);
+      } else {
+        handlerSvc.remove(mimeInfo);
+      }
+    }
+  }
+
+  // Restore old pref
+  registerCleanupFunction(function () {
+    MockFilePicker.cleanup();
+    SpecialPowers.setBoolPref(
+      "browser.download.useDownloadDir",
+      useDownloadDir
+    );
+  });
+});
+
+function testType(isValid, type, params = "") {
+  const TEST_JSON_URL = "data:" + type + params + ",[1,2,3]";
+  return addJsonViewTab(TEST_JSON_URL).then(
+    async function () {
+      ok(isValid, "The JSON Viewer should only load for valid content types.");
+      await SpecialPowers.spawn(
+        gBrowser.selectedBrowser,
+        [type],
+        function (contentType) {
+          is(
+            content.document.contentType,
+            contentType,
+            "Got the right content type"
+          );
+        }
+      );
+
+      const count = await getElementCount(".jsonPanelBox .treeTable .treeRow");
+      is(count, 3, "There must be expected number of rows");
+    },
+    function () {
+      ok(
+        !isValid,
+        "The JSON Viewer should only not load for invalid content types."
+      );
+    }
+  );
+}
diff --git a/devtools/client/jsonview/test/browser_jsonview_copy_headers.js b/devtools/client/jsonview/test/browser_jsonview_copy_headers.js
new file mode 100644
index 0000000000..faa6e43354
--- /dev/null
+++ b/devtools/client/jsonview/test/browser_jsonview_copy_headers.js
@@ -0,0 +1,38 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const TEST_JSON_URL = URL_ROOT + "valid_json.json";
+
+add_task(async function () {
+  info("Test valid JSON started");
+
+  await addJsonViewTab(TEST_JSON_URL);
+
+  // Select the RawData tab
+  await selectJsonViewContentTab("headers");
+
+  // Check displayed headers
+  const count = await getElementCount(".headersPanelBox .netHeadersGroup");
+  is(count, 2, "There must be two header groups");
+
+  const text = await getElementText(".headersPanelBox .netInfoHeadersTable");
+  isnot(text, "", "Headers text must not be empty");
+
+  const browser = gBrowser.selectedBrowser;
+
+  // Verify JSON copy into the clipboard.
+  await waitForClipboardPromise(
+    function setup() {
+      BrowserTestUtils.synthesizeMouseAtCenter(
+        ".headersPanelBox .toolbar button.copy",
+        {},
+        browser
+      );
+    },
+    function validator(value) {
+      return value.indexOf("application/json") > 0;
+    }
+  );
+});
diff --git a/devtools/client/jsonview/test/browser_jsonview_copy_json.js b/devtools/client/jsonview/test/browser_jsonview_copy_json.js
new file mode 100644
index 0000000000..56c7b3ff75
--- /dev/null
+++ b/devtools/client/jsonview/test/browser_jsonview_copy_json.js
@@ -0,0 +1,34 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const TEST_JSON_URL = URL_ROOT + "simple_json.json";
+
+add_task(async function () {
+  info("Test copy JSON started");
+
+  await addJsonViewTab(TEST_JSON_URL);
+
+  const countBefore = await getElementCount(
+    ".jsonPanelBox .treeTable .treeRow"
+  );
+  ok(countBefore == 1, "There must be one row");
+
+  const text = await getElementText(".jsonPanelBox .treeTable .treeRow");
+  is(text, 'name"value"', "There must be proper JSON displayed");
+
+  // Verify JSON copy into the clipboard.
+  const value = '{ "name": "value" }\n';
+  const browser = gBrowser.selectedBrowser;
+  const selector = ".jsonPanelBox .toolbar button.copy";
+  await waitForClipboardPromise(
+    function setup() {
+      BrowserTestUtils.synthesizeMouseAtCenter(selector, {}, browser);
+    },
+    function validator(result) {
+      const str = normalizeNewLines(result);
+      return str == value;
+    }
+  );
+});
diff --git a/devtools/client/jsonview/test/browser_jsonview_copy_rawdata.js b/devtools/client/jsonview/test/browser_jsonview_copy_rawdata.js
new file mode 100644
index 0000000000..0685b7c5d3
--- /dev/null
+++ b/devtools/client/jsonview/test/browser_jsonview_copy_rawdata.js
@@ -0,0 +1,62 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const TEST_JSON_URL = URL_ROOT + "simple_json.json";
+
+const jsonText = '{ "name": "value" }\n';
+const prettyJson = '{\n  "name": "value"\n}';
+
+add_task(async function () {
+  info("Test copy raw data started");
+
+  await addJsonViewTab(TEST_JSON_URL);
+
+  // Select the RawData tab
+  await selectJsonViewContentTab("rawdata");
+
+  // Check displayed JSON
+  const text = await getElementText(".textPanelBox .data");
+  is(text, jsonText, "Proper JSON must be displayed in DOM");
+
+  const browser = gBrowser.selectedBrowser;
+
+  // Verify JSON copy into the clipboard.
+  await waitForClipboardPromise(function setup() {
+    BrowserTestUtils.synthesizeMouseAtCenter(
+      ".textPanelBox .toolbar button.copy",
+      {},
+      browser
+    );
+  }, jsonText);
+
+  // Click 'Pretty Print' button
+  await BrowserTestUtils.synthesizeMouseAtCenter(
+    ".textPanelBox .toolbar button.prettyprint",
+    {},
+    browser
+  );
+
+  let prettyText = await getElementText(".textPanelBox .data");
+  prettyText = normalizeNewLines(prettyText);
+  ok(
+    prettyText.startsWith(prettyJson),
+    "Pretty printed JSON must be displayed"
+  );
+
+  // Verify JSON copy into the clipboard.
+  await waitForClipboardPromise(
+    function setup() {
+      BrowserTestUtils.synthesizeMouseAtCenter(
+        ".textPanelBox .toolbar button.copy",
+        {},
+        browser
+      );
+    },
+    function validator(value) {
+      const str = normalizeNewLines(value);
+      return str == prettyJson;
+    }
+  );
+});
diff --git a/devtools/client/jsonview/test/browser_jsonview_csp_json.js b/devtools/client/jsonview/test/browser_jsonview_csp_json.js
new file mode 100644
index 0000000000..4416bccf15
--- /dev/null
+++ b/devtools/client/jsonview/test/browser_jsonview_csp_json.js
@@ -0,0 +1,33 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const TEST_JSON_URL = URL_ROOT + "csp_json.json";
+
+add_task(async function () {
+  info("Test CSP JSON started");
+
+  const tab = await addJsonViewTab(TEST_JSON_URL);
+
+  const count = await getElementCount(".jsonPanelBox .treeTable .treeRow");
+  is(count, 1, "There must be one row");
+
+  // The JSON Viewer alters the CSP, but the displayed header should be the original one
+  await selectJsonViewContentTab("headers");
+  await SpecialPowers.spawn(tab.linkedBrowser, [], async function () {
+    const responseHeaders = content.document.querySelector(".netHeadersGroup");
+    const names = responseHeaders.querySelectorAll(".netInfoParamName");
+    let found = false;
+    for (const name of names) {
+      if (name.textContent.toLowerCase() == "content-security-policy") {
+        ok(!found, "The CSP header only appears once");
+        found = true;
+        const value = name.nextElementSibling.textContent;
+        const expected = "default-src 'none'; base-uri 'none';";
+        is(value, expected, "The CSP value has not been altered");
+      }
+    }
+    ok(found, "The CSP header is present");
+  });
+});
diff --git a/devtools/client/jsonview/test/browser_jsonview_data_blocking.js b/devtools/client/jsonview/test/browser_jsonview_data_blocking.js
new file mode 100644
index 0000000000..f36d39dcc8
--- /dev/null
+++ b/devtools/client/jsonview/test/browser_jsonview_data_blocking.js
@@ -0,0 +1,174 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const TEST_PATH = getRootDirectory(gTestPath).replace(
+  "chrome://mochitests/content",
+  "http://example.com"
+);
+
+const JSON_VIEW_MIME_TYPE = "application/vnd.mozilla.json.view";
+const nullP = Services.scriptSecurityManager.createNullPrincipal({});
+
+// We need 3 levels of nesting just to get to run something against a content
+// page, so the devtools limit of 4 levels of nesting don't help:
+/* eslint max-nested-callbacks: 0 */
+
+/**
+ * Check that we don't expose a JSONView object on data: URI windows where
+ * we block the load.
+ */
+add_task(async function test_blocked_data_exposure() {
+  await SpecialPowers.pushPrefEnv({
+    set: [["security.data_uri.block_toplevel_data_uri_navigations", true]],
+  });
+  await BrowserTestUtils.withNewTab(TEST_PATH + "empty.html", async browser => {
+    const tabCount = gBrowser.tabs.length;
+    await SpecialPowers.spawn(browser, [], function () {
+      content.w = content.window.open(
+        "data:application/vnd.mozilla.json.view,1",
+        "_blank"
+      );
+      ok(
+        !Cu.waiveXrays(content.w).JSONView,
+        "Should not have created a JSON View object"
+      );
+      // We need to wait for the JSON view machinery to actually have a chance to run.
+      // We have no way to detect that it has or hasn't, so a setTimeout is the best we
+      // can do, unfortunately.
+      return new Promise(resolve => {
+        content.setTimeout(function () {
+          // Putting the resolve before the check to avoid JS errors potentially causing
+          // the test to time out.
+          resolve();
+          ok(
+            !Cu.waiveXrays(content.w).JSONView,
+            "Should still not have a JSON View object"
+          );
+        }, 1000);
+      });
+    });
+    // Without this, if somehow the data: protocol blocker stops working, the
+    // test would just keep passing.
+    is(
+      tabCount,
+      gBrowser.tabs.length,
+      "Haven't actually opened a new window/tab"
+    );
+  });
+});
+
+/**
+ * Check that aborted channels also abort sending data from the stream converter.
+ */
+add_task(async function test_converter_abort_should_stop_data_sending() {
+  const loadInfo = NetUtil.newChannel({
+    uri: Services.io.newURI("data:text/plain,"),
+    loadingPrincipal: nullP,
+    securityFlags: Ci.nsILoadInfo.SEC_ALLOW_CROSS_ORIGIN_SEC_CONTEXT_IS_NULL,
+    contentPolicyType: Ci.nsIContentPolicy.TYPE_OTHER,
+  }).loadInfo;
+  // Stub all the things.
+  const chan = {
+    QueryInterface: ChromeUtils.generateQI([
+      "nsIChannel",
+      "nsIWritablePropertyBag",
+    ]),
+    URI: Services.io.newURI("data:application/json,{}"),
+    // loadinfo is builtinclass, need to actually have one:
+    loadInfo,
+    notificationCallbacks: {
+      QueryInterface: ChromeUtils.generateQI(["nsIInterfaceRequestor"]),
+      getInterface() {
+        // We want a loadcontext here, which is also builtinclass, can't stub.
+        return docShell;
+      },
+    },
+    status: Cr.NS_OK,
+    setProperty() {},
+  };
+  let onStartFired = false;
+  const listener = {
+    QueryInterface: ChromeUtils.generateQI(["nsIStreamListener"]),
+    onStartRequest() {
+      onStartFired = true;
+      // This should force the converter to abort, too:
+      chan.status = Cr.NS_BINDING_ABORTED;
+    },
+    onDataAvailable() {
+      ok(false, "onDataAvailable should never fire");
+    },
+  };
+  const conv = Cc[
+    "@mozilla.org/streamconv;1?from=" + JSON_VIEW_MIME_TYPE + "&to=*/*"
+  ].createInstance(Ci.nsIStreamConverter);
+  conv.asyncConvertData(
+    "application/vnd.mozilla.json.view",
+    "text/html",
+    listener,
+    null
+  );
+  conv.onStartRequest(chan);
+  ok(onStartFired, "Should have fired onStartRequest");
+});
+
+/**
+ * Check that principal mismatches break things. Note that we're stubbing
+ * the window associated with the channel to be a browser window; the
+ * converter should be bailing out because the window's principal won't
+ * match the null principal to which the converter tries to reset the
+ * inheriting principal of the channel.
+ */
+add_task(async function test_converter_principal_needs_matching() {
+  const loadInfo = NetUtil.newChannel({
+    uri: Services.io.newURI("data:text/plain,"),
+    loadingPrincipal: nullP,
+    securityFlags: Ci.nsILoadInfo.SEC_ALLOW_CROSS_ORIGIN_SEC_CONTEXT_IS_NULL,
+    contentPolicyType: Ci.nsIContentPolicy.TYPE_OTHER,
+  }).loadInfo;
+  // Stub all the things.
+  const chan = {
+    QueryInterface: ChromeUtils.generateQI([
+      "nsIChannel",
+      "nsIWritablePropertyBag",
+    ]),
+    URI: Services.io.newURI("data:application/json,{}"),
+    // loadinfo is builtinclass, need to actually have one:
+    loadInfo,
+    notificationCallbacks: {
+      QueryInterface: ChromeUtils.generateQI(["nsIInterfaceRequestor"]),
+      getInterface() {
+        // We want a loadcontext here, which is also builtinclass, can't stub.
+        return docShell;
+      },
+    },
+    status: Cr.NS_OK,
+    setProperty() {},
+    cancel(arg) {
+      this.status = arg;
+    },
+  };
+  let onStartFired = false;
+  const listener = {
+    QueryInterface: ChromeUtils.generateQI(["nsIStreamListener"]),
+    onStartRequest() {
+      onStartFired = true;
+    },
+    onDataAvailable() {
+      ok(false, "onDataAvailable should never fire");
+    },
+  };
+  const conv = Cc[
+    "@mozilla.org/streamconv;1?from=" + JSON_VIEW_MIME_TYPE + "&to=*/*"
+  ].createInstance(Ci.nsIStreamConverter);
+  conv.asyncConvertData(
+    "application/vnd.mozilla.json.view",
+    "text/html",
+    listener,
+    null
+  );
+  conv.onStartRequest(chan);
+  ok(onStartFired, "Should have fired onStartRequest");
+  is(chan.status, Cr.NS_BINDING_ABORTED, "Should have been aborted.");
+});
diff --git a/devtools/client/jsonview/test/browser_jsonview_empty_object.js b/devtools/client/jsonview/test/browser_jsonview_empty_object.js
new file mode 100644
index 0000000000..af3dfbc007
--- /dev/null
+++ b/devtools/client/jsonview/test/browser_jsonview_empty_object.js
@@ -0,0 +1,48 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+function testRootObject(objExpr, summary = objExpr) {
+  return async function () {
+    info("Test JSON with root empty object " + objExpr + " started");
+
+    const TEST_JSON_URL = "data:application/json," + objExpr;
+    await addJsonViewTab(TEST_JSON_URL);
+
+    const objectText = await getElementText(".jsonPanelBox .panelContent");
+    is(objectText, summary, "The root object " + objExpr + " is visible");
+  };
+}
+
+function testNestedObject(objExpr, summary = objExpr) {
+  return async function () {
+    info("Test JSON with nested empty object " + objExpr + " started");
+
+    const TEST_JSON_URL = "data:application/json,[" + objExpr + "]";
+    await addJsonViewTab(TEST_JSON_URL);
+
+    const objectCellCount = await getElementCount(
+      ".jsonPanelBox .treeTable .objectCell"
+    );
+    is(objectCellCount, 1, "There must be one object cell");
+
+    const objectCellText = await getElementText(
+      ".jsonPanelBox .treeTable .objectCell"
+    );
+    is(objectCellText, summary, objExpr + " has a visible summary");
+
+    // Collapse auto-expanded node.
+    await clickJsonNode(".jsonPanelBox .treeTable .treeLabel");
+
+    const textAfter = await getElementText(
+      ".jsonPanelBox .treeTable .objectCell"
+    );
+    is(textAfter, summary, objExpr + " still has a visible summary");
+  };
+}
+
+add_task(testRootObject("null"));
+add_task(testNestedObject("null"));
+add_task(testNestedObject("[]"));
+add_task(testNestedObject("{}"));
diff --git a/devtools/client/jsonview/test/browser_jsonview_encoding.js b/devtools/client/jsonview/test/browser_jsonview_encoding.js
new file mode 100644
index 0000000000..be49af39d2
--- /dev/null
+++ b/devtools/client/jsonview/test/browser_jsonview_encoding.js
@@ -0,0 +1,67 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+add_task(async function () {
+  info("Test JSON encoding started");
+
+  const bom = "%EF%BB%BF"; // UTF-8 BOM
+  const tests = [
+    {
+      input: bom,
+      output: "",
+    },
+    {
+      input: "%FE%FF", // UTF-16BE BOM
+      output: "\uFFFD\uFFFD",
+    },
+    {
+      input: "%FF%FE", // UTF-16LE BOM
+      output: "\uFFFD\uFFFD",
+    },
+    {
+      input: bom + "%30",
+      output: "0",
+    },
+    {
+      input: bom + bom,
+      output: "\uFEFF",
+    },
+    {
+      input: "%00%61",
+      output: "\u0000a",
+    },
+    {
+      input: "%61%00",
+      output: "a\u0000",
+    },
+    {
+      input: "%30%FF",
+      output: "0�",
+    },
+    {
+      input: "%C3%A0",
+      output: "à",
+    },
+    {
+      input: "%E2%9D%A4",
+      output: "❤",
+    },
+    {
+      input: "%F0%9F%9A%80",
+      output: "🚀",
+    },
+  ];
+
+  for (const { input, output } of tests) {
+    info("Test decoding of " + JSON.stringify(input) + ".");
+
+    await addJsonViewTab("data:application/json," + input);
+    await selectJsonViewContentTab("rawdata");
+
+    // Check displayed data.
+    const data = await getElementText(".textPanelBox .data");
+    is(data, output, "The right data has been received.");
+  }
+});
diff --git a/devtools/client/jsonview/test/browser_jsonview_expand_collapse.js b/devtools/client/jsonview/test/browser_jsonview_expand_collapse.js
new file mode 100644
index 0000000000..6b681ff0cc
--- /dev/null
+++ b/devtools/client/jsonview/test/browser_jsonview_expand_collapse.js
@@ -0,0 +1,61 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+XPCOMUtils.defineLazyGetter(this, "jsonViewStrings", () => {
+  return Services.strings.createBundle(
+    "chrome://devtools/locale/jsonview.properties"
+  );
+});
+
+const TEST_JSON_URL = URL_ROOT + "array_json.json";
+const EXPAND_THRESHOLD = 100 * 1024;
+
+add_task(async function () {
+  info("Test expand/collapse small JSON started");
+
+  await addJsonViewTab(TEST_JSON_URL);
+
+  /* Initial sanity check */
+  const countBefore = await getElementCount(".treeRow");
+  is(countBefore, 6, "There must be six rows");
+
+  /* Test the "Collapse All" button */
+  let selector = ".jsonPanelBox .toolbar button.collapse";
+  await clickJsonNode(selector);
+  let countAfter = await getElementCount(".treeRow");
+  is(countAfter, 3, "There must be three rows");
+
+  /* Test the "Expand All" button */
+  selector = ".jsonPanelBox .toolbar button.expand";
+  is(
+    await getElementText(selector),
+    jsonViewStrings.GetStringFromName("jsonViewer.ExpandAll"),
+    "Expand button doesn't warn that the action will be slow"
+  );
+  await clickJsonNode(selector);
+  countAfter = await getElementCount(".treeRow");
+  is(countAfter, 6, "There must be six expanded rows");
+});
+
+add_task(async function () {
+  info("Test expand button for big JSON started");
+
+  const json = JSON.stringify({
+    data: Array(1e5)
+      .fill()
+      .map(x => "hoot"),
+    status: "ok",
+  });
+  ok(
+    json.length > EXPAND_THRESHOLD,
+    "The generated JSON must be larger than 100kB"
+  );
+  await addJsonViewTab("data:application/json," + json);
+  is(
+    await getElementText(".jsonPanelBox .toolbar button.expand"),
+    jsonViewStrings.GetStringFromName("jsonViewer.ExpandAllSlow"),
+    "Expand button warns that the action will be slow"
+  );
+});
diff --git a/devtools/client/jsonview/test/browser_jsonview_filter.js b/devtools/client/jsonview/test/browser_jsonview_filter.js
new file mode 100644
index 0000000000..1dd093da5b
--- /dev/null
+++ b/devtools/client/jsonview/test/browser_jsonview_filter.js
@@ -0,0 +1,27 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const TEST_JSON_URL = URL_ROOT + "array_json.json";
+
+add_task(async function () {
+  info("Test valid JSON started");
+
+  await addJsonViewTab(TEST_JSON_URL);
+
+  const count = await getElementCount(".jsonPanelBox .treeTable .treeRow");
+  is(count, 6, "There must be expected number of rows");
+
+  // XXX use proper shortcut to focus the filter box
+  // as soon as bug Bug 1178771 is fixed.
+  await sendString("h", ".jsonPanelBox .searchBox");
+
+  // The filtering is done asynchronously so, we need to wait.
+  await waitForFilter();
+
+  const hiddenCount = await getElementCount(
+    ".jsonPanelBox .treeTable .treeRow.hidden"
+  );
+  is(hiddenCount, 4, "There must be expected number of hidden rows");
+});
diff --git a/devtools/client/jsonview/test/browser_jsonview_filter_clear.js b/devtools/client/jsonview/test/browser_jsonview_filter_clear.js
new file mode 100644
index 0000000000..70ece7ee03
--- /dev/null
+++ b/devtools/client/jsonview/test/browser_jsonview_filter_clear.js
@@ -0,0 +1,85 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const TEST_JSON_URL = URL_ROOT + "array_json.json";
+const filterClearButton = "button.devtools-searchinput-clear";
+
+function clickAndWaitForFilterClear(selector) {
+  return SpecialPowers.spawn(gBrowser.selectedBrowser, [selector], sel => {
+    content.document.querySelector(sel).click();
+
+    const rows = Array.from(
+      content.document.querySelectorAll(".jsonPanelBox .treeTable .treeRow")
+    );
+
+    // If there are no hiddens rows
+    if (!rows.some(r => r.classList.contains("hidden"))) {
+      info("The view has been cleared, no need for mutationObserver");
+      return Promise.resolve();
+    }
+
+    return new Promise(resolve => {
+      // Wait until we have 0 hidden rows
+      const observer = new content.MutationObserver(function (mutations) {
+        info("New mutation ! ");
+        info(`${mutations}`);
+        for (let i = 0; i < mutations.length; i++) {
+          const mutation = mutations[i];
+          info(`type: ${mutation.type}`);
+          info(`attributeName: ${mutation.attributeName}`);
+          info(`attributeNamespace: ${mutation.attributeNamespace}`);
+          info(`oldValue: ${mutation.oldValue}`);
+          if (mutation.attributeName == "class") {
+            if (!rows.some(r => r.classList.contains("hidden"))) {
+              info("resolving mutationObserver");
+              observer.disconnect();
+              resolve();
+              break;
+            }
+          }
+        }
+      });
+
+      const parent = content.document.querySelector("tbody");
+      observer.observe(parent, { attributes: true, subtree: true });
+    });
+  });
+}
+
+add_task(async function () {
+  info("Test filter input is cleared when pressing the clear button");
+
+  await addJsonViewTab(TEST_JSON_URL);
+
+  // Type "honza" in the filter input
+  const count = await getElementCount(".jsonPanelBox .treeTable .treeRow");
+  is(count, 6, "There must be expected number of rows");
+  await sendString("honza", ".jsonPanelBox .searchBox");
+  await waitForFilter();
+
+  const filterInputValue = await getFilterInputValue();
+  is(filterInputValue, "honza", "Filter input shoud be filled");
+
+  // Check the json is filtered
+  const hiddenCount = await getElementCount(
+    ".jsonPanelBox .treeTable .treeRow.hidden"
+  );
+  is(hiddenCount, 4, "There must be expected number of hidden rows");
+
+  info("Click on the close button");
+  await clickAndWaitForFilterClear(filterClearButton);
+
+  // Check the json is not filtered and the filter input is empty
+  const newfilterInputValue = await getFilterInputValue();
+  is(newfilterInputValue, "", "Filter input should be empty");
+  const newCount = await getElementCount(
+    ".jsonPanelBox .treeTable .treeRow.hidden"
+  );
+  is(newCount, 0, "There must be expected number of rows");
+});
+
+function getFilterInputValue() {
+  return getElementAttr(".devtools-filterinput", "value");
+}
diff --git a/devtools/client/jsonview/test/browser_jsonview_ignore_charset.js b/devtools/client/jsonview/test/browser_jsonview_ignore_charset.js
new file mode 100644
index 0000000000..ffd00a35e3
--- /dev/null
+++ b/devtools/client/jsonview/test/browser_jsonview_ignore_charset.js
@@ -0,0 +1,18 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+add_task(async function () {
+  info("Test ignored charset parameter started");
+
+  const encodedChar = "%E2%9D%A4"; // In UTF-8 this is a heavy black heart
+  const result = "❤";
+  const TEST_JSON_URL = "data:application/json;charset=ANSI," + encodedChar;
+
+  await addJsonViewTab(TEST_JSON_URL);
+  await selectJsonViewContentTab("rawdata");
+
+  const text = await getElementText(".textPanelBox .data");
+  is(text, result, "The charset parameter is ignored and UTF-8 is used.");
+});
diff --git a/devtools/client/jsonview/test/browser_jsonview_initial_focus.js b/devtools/client/jsonview/test/browser_jsonview_initial_focus.js
new file mode 100644
index 0000000000..71b0623ce5
--- /dev/null
+++ b/devtools/client/jsonview/test/browser_jsonview_initial_focus.js
@@ -0,0 +1,33 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const VALID_JSON_URL = URL_ROOT + "valid_json.json";
+
+add_task(async function () {
+  info("Test focus JSON view started");
+  await addJsonViewTab(VALID_JSON_URL);
+
+  await SpecialPowers.spawn(gBrowser.selectedBrowser, [], async () => {
+    const scroller = content.document.getElementById("json-scrolling-panel");
+    ok(scroller, "Found the scrollable area");
+    is(
+      content.document.activeElement,
+      scroller,
+      "Scrollable area initially focused"
+    );
+  });
+  await reloadBrowser();
+  await SpecialPowers.spawn(gBrowser.selectedBrowser, [], async () => {
+    const scroller = await ContentTaskUtils.waitForCondition(
+      () => content.document.getElementById("json-scrolling-panel"),
+      "Wait for the panel to be loaded"
+    );
+    is(
+      content.document.activeElement,
+      scroller,
+      "Scrollable area focused after reload"
+    );
+  });
+});
diff --git a/devtools/client/jsonview/test/browser_jsonview_invalid_json.js b/devtools/client/jsonview/test/browser_jsonview_invalid_json.js
new file mode 100644
index 0000000000..461030959b
--- /dev/null
+++ b/devtools/client/jsonview/test/browser_jsonview_invalid_json.js
@@ -0,0 +1,18 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const TEST_JSON_URL = URL_ROOT + "invalid_json.json";
+
+add_task(async function () {
+  info("Test invalid JSON started");
+
+  await addJsonViewTab(TEST_JSON_URL);
+
+  const count = await getElementCount(".jsonPanelBox .treeTable .treeRow");
+  ok(count == 0, "There must be no row");
+
+  const text = await getElementText(".jsonPanelBox .jsonParseError");
+  ok(text, "There must be an error description");
+});
diff --git a/devtools/client/jsonview/test/browser_jsonview_manifest.js b/devtools/client/jsonview/test/browser_jsonview_manifest.js
new file mode 100644
index 0000000000..8072324cf1
--- /dev/null
+++ b/devtools/client/jsonview/test/browser_jsonview_manifest.js
@@ -0,0 +1,15 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const TEST_JSON_URL = URL_ROOT + "manifest_json.json";
+
+add_task(async function () {
+  info("Test manifest JSON file started");
+
+  await addJsonViewTab(TEST_JSON_URL);
+
+  const count = await getElementCount(".jsonPanelBox .treeTable .treeRow");
+  is(count, 37, "There must be expected number of rows");
+});
diff --git a/devtools/client/jsonview/test/browser_jsonview_nojs.js b/devtools/client/jsonview/test/browser_jsonview_nojs.js
new file mode 100644
index 0000000000..38459617a2
--- /dev/null
+++ b/devtools/client/jsonview/test/browser_jsonview_nojs.js
@@ -0,0 +1,26 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+add_task(async function () {
+  info("Test JSON without JavaScript started.");
+
+  const oldPref = Services.prefs.getBoolPref("javascript.enabled");
+  Services.prefs.setBoolPref("javascript.enabled", false);
+
+  const TEST_JSON_URL = "data:application/json,[1,2,3]";
+
+  // "uninitialized" will be the last app readyState because JS is disabled.
+  await addJsonViewTab(TEST_JSON_URL, { appReadyState: "uninitialized" });
+
+  info("Checking visible text contents.");
+
+  const text = await SpecialPowers.spawn(gBrowser.selectedBrowser, [], () => {
+    const element = content.document.querySelector("html");
+    return element ? element.innerText : null;
+  });
+  is(text, "[1,2,3]", "The raw source should be visible.");
+
+  Services.prefs.setBoolPref("javascript.enabled", oldPref);
+});
diff --git a/devtools/client/jsonview/test/browser_jsonview_nul.js b/devtools/client/jsonview/test/browser_jsonview_nul.js
new file mode 100644
index 0000000000..746846796b
--- /dev/null
+++ b/devtools/client/jsonview/test/browser_jsonview_nul.js
@@ -0,0 +1,15 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+add_task(async function () {
+  info("Test JSON with NUL started.");
+
+  const TEST_JSON_URL = 'data:application/json,"foo_%00_bar"';
+  await addJsonViewTab(TEST_JSON_URL);
+
+  await selectJsonViewContentTab("rawdata");
+  const rawData = await getElementText(".textPanelBox .data");
+  is(rawData, '"foo_\u0000_bar"', "The NUL character has been preserved.");
+});
diff --git a/devtools/client/jsonview/test/browser_jsonview_object-type.js b/devtools/client/jsonview/test/browser_jsonview_object-type.js
new file mode 100644
index 0000000000..08b9ed865c
--- /dev/null
+++ b/devtools/client/jsonview/test/browser_jsonview_object-type.js
@@ -0,0 +1,25 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const { ELLIPSIS } = require("resource://devtools/shared/l10n.js");
+
+add_task(async function () {
+  info("Test Object type property started");
+
+  const TEST_JSON_URL = 'data:application/json,{"x":{"type":"string"}}';
+  await addJsonViewTab(TEST_JSON_URL);
+
+  let count = await getElementCount(".jsonPanelBox .treeTable .treeRow");
+  is(count, 2, "There must be two rows");
+
+  // Collapse auto-expanded node.
+  await clickJsonNode(".jsonPanelBox .treeTable .treeLabel");
+
+  count = await getElementCount(".jsonPanelBox .treeTable .treeRow");
+  is(count, 1, "There must be one row");
+
+  const label = await getElementText(".jsonPanelBox .treeTable .objectCell");
+  is(label, `{${ELLIPSIS}}`, "The label must be indicating an object");
+});
diff --git a/devtools/client/jsonview/test/browser_jsonview_row_selection.js b/devtools/client/jsonview/test/browser_jsonview_row_selection.js
new file mode 100644
index 0000000000..300ac40a03
--- /dev/null
+++ b/devtools/client/jsonview/test/browser_jsonview_row_selection.js
@@ -0,0 +1,245 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+add_task(async function () {
+  info("Test 1 JSON row selection started");
+
+  // Create a tall JSON so that there is a scrollbar.
+  const numRows = 1e3;
+  const json = JSON.stringify(
+    Array(numRows)
+      .fill()
+      .map((_, i) => i)
+  );
+  const tab = await addJsonViewTab("data:application/json," + json);
+
+  is(
+    await getElementCount(".treeRow"),
+    numRows,
+    "Got the expected number of rows."
+  );
+  await assertRowSelected(null);
+
+  // Focus the tree and select first row.
+  await SpecialPowers.spawn(gBrowser.selectedBrowser, [], function () {
+    const tree = content.document.querySelector(".treeTable");
+    tree.focus();
+    is(tree, content.document.activeElement, "Tree should be focused");
+    content.document.querySelector(".treeRow:nth-child(1)").click();
+  });
+  await assertRowSelected(1);
+
+  await SpecialPowers.spawn(gBrowser.selectedBrowser, [], function () {
+    const scroller = content.document.querySelector(
+      ".jsonPanelBox .panelContent"
+    );
+    ok(scroller.clientHeight < scroller.scrollHeight, "There is a scrollbar.");
+    is(scroller.scrollTop, 0, "Initially scrolled to the top.");
+  });
+
+  // Select last row.
+  await BrowserTestUtils.synthesizeKey("VK_END", {}, tab.linkedBrowser);
+  await assertRowSelected(numRows);
+
+  await SpecialPowers.spawn(gBrowser.selectedBrowser, [], function () {
+    const scroller = content.document.querySelector(
+      ".jsonPanelBox .panelContent"
+    );
+    is(
+      scroller.scrollTop + scroller.clientHeight,
+      scroller.scrollHeight,
+      "Scrolled to the bottom."
+    );
+    // Click to select 2nd row.
+    content.document.querySelector(".treeRow:nth-child(2)").click();
+  });
+  await assertRowSelected(2);
+
+  await SpecialPowers.spawn(gBrowser.selectedBrowser, [], function () {
+    const scroller = content.document.querySelector(
+      ".jsonPanelBox .panelContent"
+    );
+    ok(scroller.scrollTop > 0, "Not scrolled to the top.");
+    // Synthesize up arrow key to select first row.
+    content.document.querySelector(".treeTable").focus();
+  });
+  await BrowserTestUtils.synthesizeKey("VK_UP", {}, tab.linkedBrowser);
+  await assertRowSelected(1);
+  await SpecialPowers.spawn(gBrowser.selectedBrowser, [], function () {
+    const scroller = content.document.querySelector(
+      ".jsonPanelBox .panelContent"
+    );
+    is(scroller.scrollTop, 0, "Scrolled to the top.");
+  });
+});
+
+add_task(async function () {
+  info("Test 2 JSON row selection started");
+
+  const numRows = 4;
+  const tab = await addJsonViewTab("data:application/json,[0,1,2,3]");
+
+  is(
+    await getElementCount(".treeRow"),
+    numRows,
+    "Got the expected number of rows."
+  );
+  await assertRowSelected(null);
+
+  // Click to select first row.
+  await clickJsonNode(".treeRow:first-child");
+  await assertRowSelected(1);
+
+  // Synthesize multiple down arrow keydowns to select following rows.
+  await SpecialPowers.spawn(tab.linkedBrowser, [], function () {
+    content.document.querySelector(".treeTable").focus();
+  });
+  for (let i = 2; i < numRows; ++i) {
+    await BrowserTestUtils.synthesizeKey(
+      "VK_DOWN",
+      { type: "keydown" },
+      tab.linkedBrowser
+    );
+    await assertRowSelected(i);
+  }
+
+  // Now synthesize the keyup, this shouldn't change selected row.
+  await BrowserTestUtils.synthesizeKey(
+    "VK_DOWN",
+    { type: "keyup" },
+    tab.linkedBrowser
+  );
+  await wait(500);
+  await assertRowSelected(numRows - 1);
+
+  // Finally, synthesize keydown with a modifier, this also shouldn't change selected row.
+  await BrowserTestUtils.synthesizeKey(
+    "VK_DOWN",
+    { type: "keydown", shiftKey: true },
+    tab.linkedBrowser
+  );
+  await wait(500);
+  await assertRowSelected(numRows - 1);
+});
+
+add_task(async function () {
+  info("Test 3 JSON row selection started");
+
+  // Create a JSON with a row taller than the panel.
+  const json = JSON.stringify([0, "a ".repeat(1e4), 1]);
+  const tab = await addJsonViewTab("data:application/json," + encodeURI(json));
+
+  is(await getElementCount(".treeRow"), 3, "Got the expected number of rows.");
+  await assertRowSelected(null);
+  await SpecialPowers.spawn(gBrowser.selectedBrowser, [], function () {
+    const scroller = content.document.querySelector(
+      ".jsonPanelBox .panelContent"
+    );
+    const row = content.document.querySelector(".treeRow:nth-child(2)");
+    ok(
+      scroller.clientHeight < row.clientHeight,
+      "The row is taller than the scroller."
+    );
+    is(scroller.scrollTop, 0, "Initially scrolled to the top.");
+
+    // Select the tall row.
+    content.document.querySelector(".treeTable").focus();
+    row.click();
+  });
+  await assertRowSelected(2);
+  await SpecialPowers.spawn(gBrowser.selectedBrowser, [], function () {
+    const scroller = content.document.querySelector(
+      ".jsonPanelBox .panelContent"
+    );
+    is(
+      scroller.scrollTop,
+      0,
+      "When the row is visible, do not scroll on click."
+    );
+  });
+
+  // Select the last row.
+  await BrowserTestUtils.synthesizeKey("VK_DOWN", {}, tab.linkedBrowser);
+  await assertRowSelected(3);
+  await SpecialPowers.spawn(gBrowser.selectedBrowser, [], function () {
+    const scroller = content.document.querySelector(
+      ".jsonPanelBox .panelContent"
+    );
+    is(
+      scroller.scrollTop + scroller.offsetHeight,
+      scroller.scrollHeight,
+      "Scrolled to the bottom."
+    );
+
+    // Select the tall row.
+    const row = content.document.querySelector(".treeRow:nth-child(2)");
+    row.click();
+  });
+
+  await assertRowSelected(2);
+  const scroll = await SpecialPowers.spawn(
+    gBrowser.selectedBrowser,
+    [],
+    function () {
+      const scroller = content.document.querySelector(
+        ".jsonPanelBox .panelContent"
+      );
+      const row = content.document.querySelector(".treeRow:nth-child(2)");
+      is(
+        scroller.scrollTop + scroller.offsetHeight,
+        scroller.scrollHeight,
+        "Scrolled to the bottom. When the row is visible, do not scroll on click."
+      );
+
+      // Scroll up a bit, so that both the top and bottom of the row are not visible.
+      const scrollPos = (scroller.scrollTop = Math.ceil(
+        (scroller.scrollTop + row.offsetTop) / 2
+      ));
+      ok(
+        scroller.scrollTop > row.offsetTop,
+        "The top of the row is not visible."
+      );
+      ok(
+        scroller.scrollTop + scroller.offsetHeight <
+          row.offsetTop + row.offsetHeight,
+        "The bottom of the row is not visible."
+      );
+
+      // Select the tall row.
+      row.click();
+      return scrollPos;
+    }
+  );
+
+  await assertRowSelected(2);
+  await SpecialPowers.spawn(
+    gBrowser.selectedBrowser,
+    [scroll],
+    function (scrollPos) {
+      const scroller = content.document.querySelector(
+        ".jsonPanelBox .panelContent"
+      );
+      is(scroller.scrollTop, scrollPos, "Scroll did not change");
+    }
+  );
+});
+
+async function assertRowSelected(rowNum) {
+  const idx = await SpecialPowers.spawn(
+    gBrowser.selectedBrowser,
+    [],
+    function () {
+      return [].indexOf.call(
+        content.document.querySelectorAll(".treeRow"),
+        content.document.querySelector(".treeRow.selected")
+      );
+    }
+  );
+  is(
+    idx + 1,
+    +rowNum,
+    `${rowNum ? "The row #" + rowNum : "No row"} is selected.`
+  );
+}
diff --git a/devtools/client/jsonview/test/browser_jsonview_save_json.js b/devtools/client/jsonview/test/browser_jsonview_save_json.js
new file mode 100644
index 0000000000..506967df00
--- /dev/null
+++ b/devtools/client/jsonview/test/browser_jsonview_save_json.js
@@ -0,0 +1,159 @@
+/* eslint-disable no-unused-vars, no-undef */
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const saveButton = "button.save";
+const prettifyButton = "button.prettyprint";
+
+const { MockFilePicker } = SpecialPowers;
+MockFilePicker.init(window);
+MockFilePicker.returnValue = MockFilePicker.returnOK;
+
+Services.scriptloader.loadSubScript(
+  "chrome://mochitests/content/browser/toolkit/content/tests/browser/common/mockTransfer.js",
+  this
+);
+
+function awaitSavedFileContents(name, ext) {
+  return new Promise((resolve, reject) => {
+    MockFilePicker.showCallback = fp => {
+      try {
+        ok(true, "File picker was opened");
+        const fileName = fp.defaultString;
+        is(
+          fileName,
+          name,
+          "File picker should provide the correct default filename."
+        );
+        is(
+          fp.defaultExtension,
+          ext,
+          "File picker should provide the correct default file extension."
+        );
+        const destFile = destDir.clone();
+        destFile.append(fileName);
+        MockFilePicker.setFiles([destFile]);
+        MockFilePicker.showCallback = null;
+        mockTransferCallback = async function (downloadSuccess) {
+          try {
+            ok(
+              downloadSuccess,
+              "JSON should have been downloaded successfully"
+            );
+            ok(destFile.exists(), "The downloaded file should exist.");
+            const { path } = destFile;
+            await BrowserTestUtils.waitForCondition(() => IOUtils.exists(path));
+            await BrowserTestUtils.waitForCondition(async () => {
+              const { size } = await IOUtils.stat(path);
+              return size > 0;
+            });
+            const buffer = await IOUtils.read(path);
+            resolve(new TextDecoder().decode(buffer));
+          } catch (error) {
+            reject(error);
+          }
+        };
+      } catch (error) {
+        reject(error);
+      }
+    };
+  });
+}
+
+function createTemporarySaveDirectory() {
+  const saveDir = Services.dirsvc.get("TmpD", Ci.nsIFile);
+  saveDir.append("jsonview-testsavedir");
+  if (!saveDir.exists()) {
+    info("Creating temporary save directory.");
+    saveDir.create(Ci.nsIFile.DIRECTORY_TYPE, 0o755);
+  }
+  info("Temporary save directory: " + saveDir.path);
+  return saveDir;
+}
+
+const destDir = createTemporarySaveDirectory();
+mockTransferRegisterer.register();
+MockFilePicker.displayDirectory = destDir;
+registerCleanupFunction(function () {
+  mockTransferRegisterer.unregister();
+  MockFilePicker.cleanup();
+  destDir.remove(true);
+  ok(!destDir.exists(), "Destination dir should be removed");
+});
+
+add_task(async function () {
+  info("Test 1 save JSON started");
+
+  const JSON_FILE = "simple_json.json";
+  const TEST_JSON_URL = URL_ROOT + JSON_FILE;
+  const tab = await addJsonViewTab(TEST_JSON_URL);
+
+  const response = await fetch(new Request(TEST_JSON_URL));
+
+  info("Fetched JSON contents.");
+  const rawJSON = await response.text();
+  const prettyJSON = JSON.stringify(JSON.parse(rawJSON), null, "  ");
+  isnot(
+    rawJSON,
+    prettyJSON,
+    "Original and prettified JSON should be different."
+  );
+
+  // Attempt to save original JSON via saveBrowser (ctrl/cmd+s or "Save Page As" command).
+  let data = awaitSavedFileContents(JSON_FILE, "json");
+  saveBrowser(tab.linkedBrowser);
+  is(await data, rawJSON, "Original JSON contents should have been saved.");
+
+  // Attempt to save original JSON via "Save" button
+  data = awaitSavedFileContents(JSON_FILE, "json");
+  await clickJsonNode(saveButton);
+  info("Clicked Save button.");
+  is(await data, rawJSON, "Original JSON contents should have been saved.");
+
+  // Attempt to save prettified JSON via "Save" button
+  await selectJsonViewContentTab("rawdata");
+  info("Switched to Raw Data tab.");
+  await clickJsonNode(prettifyButton);
+  info("Clicked Pretty Print button.");
+  data = awaitSavedFileContents(JSON_FILE, "json");
+  await clickJsonNode(saveButton);
+  info("Clicked Save button.");
+  is(
+    await data,
+    prettyJSON,
+    "Prettified JSON contents should have been saved."
+  );
+
+  // saveBrowser should still save original contents.
+  data = awaitSavedFileContents(JSON_FILE, "json");
+  saveBrowser(tab.linkedBrowser);
+  is(await data, rawJSON, "Original JSON contents should have been saved.");
+});
+
+add_task(async function () {
+  info("Test 2 save JSON started");
+
+  const TEST_JSON_URL = "data:application/json,2";
+  await addJsonViewTab(TEST_JSON_URL);
+
+  info("Checking that application/json adds .json extension by default.");
+  const data = awaitSavedFileContents("Untitled.json", "json");
+  await clickJsonNode(saveButton);
+  info("Clicked Save button.");
+  is(await data, "2", "JSON contents should have been saved.");
+});
+
+add_task(async function () {
+  info("Test 3 save JSON started");
+
+  const TEST_JSON_URL = "data:application/manifest+json,3";
+  await addJsonViewTab(TEST_JSON_URL);
+
+  info("Checking that application/manifest+json does not add .json extension.");
+  const data = awaitSavedFileContents("Untitled", null);
+  await clickJsonNode(saveButton);
+  info("Clicked Save button.");
+  is(await data, "3", "JSON contents should have been saved.");
+});
diff --git a/devtools/client/jsonview/test/browser_jsonview_serviceworker.js b/devtools/client/jsonview/test/browser_jsonview_serviceworker.js
new file mode 100644
index 0000000000..37c407ecd4
--- /dev/null
+++ b/devtools/client/jsonview/test/browser_jsonview_serviceworker.js
@@ -0,0 +1,89 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const TEST_JSON_URL = URL_ROOT_SSL + "valid_json.json";
+const EMPTY_PAGE = URL_ROOT_SSL + "empty.html";
+const SW = URL_ROOT_SSL + "passthrough-sw.js";
+
+add_task(async function () {
+  info("Test valid JSON with service worker started");
+
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      ["dom.serviceWorkers.exemptFromPerDomainMax", true],
+      ["dom.serviceWorkers.enabled", true],
+      ["dom.serviceWorkers.testing.enabled", true],
+    ],
+  });
+
+  const swTab = BrowserTestUtils.addTab(gBrowser, EMPTY_PAGE);
+  const browser = gBrowser.getBrowserForTab(swTab);
+  await BrowserTestUtils.browserLoaded(browser);
+  await SpecialPowers.spawn(
+    browser,
+    [{ script: SW, scope: TEST_JSON_URL }],
+    async opts => {
+      const reg = await content.navigator.serviceWorker.register(opts.script, {
+        scope: opts.scope,
+      });
+      return new content.window.Promise(resolve => {
+        const worker = reg.installing;
+        if (worker.state === "activated") {
+          resolve();
+          return;
+        }
+        worker.addEventListener("statechange", evt => {
+          if (worker.state === "activated") {
+            resolve();
+          }
+        });
+      });
+    }
+  );
+
+  const tab = await addJsonViewTab(TEST_JSON_URL);
+
+  ok(
+    tab.linkedBrowser.contentPrincipal.isNullPrincipal,
+    "Should have null principal"
+  );
+
+  is(await countRows(), 3, "There must be three rows");
+
+  const objectCellCount = await getElementCount(
+    ".jsonPanelBox .treeTable .objectCell"
+  );
+  is(objectCellCount, 1, "There must be one object cell");
+
+  const objectCellText = await getElementText(
+    ".jsonPanelBox .treeTable .objectCell"
+  );
+  is(objectCellText, "", "The summary is hidden when object is expanded");
+
+  // Clicking the value does not collapse it (so that it can be selected and copied).
+  await clickJsonNode(".jsonPanelBox .treeTable .treeValueCell");
+  is(await countRows(), 3, "There must still be three rows");
+
+  // Clicking the label collapses the auto-expanded node.
+  await clickJsonNode(".jsonPanelBox .treeTable .treeLabel");
+  is(await countRows(), 1, "There must be one row");
+
+  await SpecialPowers.spawn(
+    browser,
+    [{ script: SW, scope: TEST_JSON_URL }],
+    async opts => {
+      const reg = await content.navigator.serviceWorker.getRegistration(
+        opts.scope
+      );
+      await reg.unregister();
+    }
+  );
+
+  BrowserTestUtils.removeTab(swTab);
+});
+
+function countRows() {
+  return getElementCount(".jsonPanelBox .treeTable .treeRow");
+}
diff --git a/devtools/client/jsonview/test/browser_jsonview_slash.js b/devtools/client/jsonview/test/browser_jsonview_slash.js
new file mode 100644
index 0000000000..f8abeca7be
--- /dev/null
+++ b/devtools/client/jsonview/test/browser_jsonview_slash.js
@@ -0,0 +1,16 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+add_task(async function () {
+  info("Test JSON with slash started.");
+
+  const TEST_JSON_URL = 'data:application/json,{"a/b":[1,2],"a":{"b":[3,4]}}';
+  await addJsonViewTab(TEST_JSON_URL);
+
+  const countBefore = await getElementCount(
+    ".jsonPanelBox .treeTable .treeRow"
+  );
+  is(countBefore, 7, "There must be seven rows");
+});
diff --git a/devtools/client/jsonview/test/browser_jsonview_theme.js b/devtools/client/jsonview/test/browser_jsonview_theme.js
new file mode 100644
index 0000000000..c66d197256
--- /dev/null
+++ b/devtools/client/jsonview/test/browser_jsonview_theme.js
@@ -0,0 +1,29 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const TEST_JSON_URL = URL_ROOT + "valid_json.json";
+
+add_task(async function () {
+  info("Test JSON theme started.");
+
+  const oldPref = Services.prefs.getCharPref("devtools.theme");
+  Services.prefs.setCharPref("devtools.theme", "light");
+
+  await addJsonViewTab(TEST_JSON_URL);
+
+  is(await getTheme(), "theme-light", "The initial theme is light");
+
+  Services.prefs.setCharPref("devtools.theme", "dark");
+  is(await getTheme(), "theme-dark", "Theme changed to dark");
+
+  Services.prefs.setCharPref("devtools.theme", "light");
+  is(await getTheme(), "theme-light", "Theme changed to light");
+
+  Services.prefs.setCharPref("devtools.theme", oldPref);
+});
+
+function getTheme() {
+  return getElementAttr(":root", "class");
+}
diff --git a/devtools/client/jsonview/test/browser_jsonview_url_linkification.js b/devtools/client/jsonview/test/browser_jsonview_url_linkification.js
new file mode 100644
index 0000000000..19d1f27f0c
--- /dev/null
+++ b/devtools/client/jsonview/test/browser_jsonview_url_linkification.js
@@ -0,0 +1,88 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const { ELLIPSIS } = require("resource://devtools/shared/l10n.js");
+
+add_task(async function () {
+  info("Test short URL linkification JSON started");
+
+  const url = "https://example.com/";
+  const tab = await addJsonViewTab(
+    "data:application/json," + JSON.stringify([url])
+  );
+  await testLinkNavigation({ browser: tab.linkedBrowser, url });
+
+  info("Switch back to the JSONViewer");
+  await BrowserTestUtils.switchTab(gBrowser, tab);
+
+  await testLinkNavigation({
+    browser: tab.linkedBrowser,
+    url,
+    clickLabel: true,
+  });
+});
+
+add_task(async function () {
+  info("Test long URL linkification JSON started");
+
+  const url = "https://example.com/" + "a".repeat(100);
+  const tab = await addJsonViewTab(
+    "data:application/json," + JSON.stringify([url])
+  );
+
+  await testLinkNavigation({ browser: tab.linkedBrowser, url });
+
+  info("Switch back to the JSONViewer");
+  await BrowserTestUtils.switchTab(gBrowser, tab);
+
+  await testLinkNavigation({
+    browser: tab.linkedBrowser,
+    url,
+    urlText: url.slice(0, 24) + ELLIPSIS + url.slice(-24),
+    clickLabel: true,
+  });
+});
+
+/**
+ * Assert that the expected link is displayed and that clicking on it navigates to the
+ * expected url.
+ *
+ * @param {Object} option object containing:
+ *        - browser (mandatory): the browser the tab will be opened in.
+ *        - url (mandatory): The url we should navigate to.
+ *        - urlText: The expected displayed text of the url.
+ *                   Falls back to `url` if not filled
+ *        - clickLabel: Should we click the label before doing assertions.
+ */
+async function testLinkNavigation({
+  browser,
+  url,
+  urlText,
+  clickLabel = false,
+}) {
+  const onTabLoaded = BrowserTestUtils.waitForNewTab(gBrowser, url);
+
+  SpecialPowers.spawn(browser, [[urlText || url, url, clickLabel]], args => {
+    const [expectedURLText, expectedURL, shouldClickLabel] = args;
+    const { document } = content;
+
+    if (shouldClickLabel === true) {
+      document.querySelector(".jsonPanelBox .treeTable .treeLabel").click();
+    }
+
+    const link = document.querySelector(
+      ".jsonPanelBox .treeTable .treeValueCell a"
+    );
+    is(link.textContent, expectedURLText, "The expected URL is displayed.");
+    is(link.href, expectedURL, "The URL was linkified.");
+
+    link.click();
+  });
+
+  const newTab = await onTabLoaded;
+  // We only need to check that newTab is truthy since
+  // BrowserTestUtils.waitForNewTab checks the URL.
+  ok(newTab, "The expected tab was opened.");
+}
diff --git a/devtools/client/jsonview/test/browser_jsonview_valid_json.js b/devtools/client/jsonview/test/browser_jsonview_valid_json.js
new file mode 100644
index 0000000000..8ffd1dc1d5
--- /dev/null
+++ b/devtools/client/jsonview/test/browser_jsonview_valid_json.js
@@ -0,0 +1,46 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const TEST_JSON_URL = URL_ROOT + "valid_json.json";
+
+add_task(async function () {
+  info("Test valid JSON started");
+
+  const tab = await addJsonViewTab(TEST_JSON_URL);
+
+  ok(
+    tab.linkedBrowser.contentPrincipal.isNullPrincipal,
+    "Should have null principal"
+  );
+
+  is(await countRows(), 3, "There must be three rows");
+
+  const objectCellCount = await getElementCount(
+    ".jsonPanelBox .treeTable .objectCell"
+  );
+  is(objectCellCount, 1, "There must be one object cell");
+
+  const objectCellText = await getElementText(
+    ".jsonPanelBox .treeTable .objectCell"
+  );
+  is(objectCellText, "", "The summary is hidden when object is expanded");
+
+  // Clicking the value does not collapse it (so that it can be selected and copied).
+  await clickJsonNode(".jsonPanelBox .treeTable .treeValueCell");
+  is(await countRows(), 3, "There must still be three rows");
+
+  // Clicking the label collapses the auto-expanded node.
+  await clickJsonNode(".jsonPanelBox .treeTable .treeLabel");
+  is(await countRows(), 1, "There must be one row");
+
+  // Collapsed nodes are preserved when switching panels.
+  await selectJsonViewContentTab("headers");
+  await selectJsonViewContentTab("json");
+  is(await countRows(), 1, "There must still be one row");
+});
+
+function countRows() {
+  return getElementCount(".jsonPanelBox .treeTable .treeRow");
+}
diff --git a/devtools/client/jsonview/test/chunked_json.sjs b/devtools/client/jsonview/test/chunked_json.sjs
new file mode 100644
index 0000000000..554b62bafd
--- /dev/null
+++ b/devtools/client/jsonview/test/chunked_json.sjs
@@ -0,0 +1,39 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
+
+const key = "json-viewer-chunked-response";
+function setResponse(response) {
+  setObjectState(key, response);
+}
+function getResponse() {
+  let response;
+  getObjectState(key, v => {
+    response = v;
+  });
+  return response;
+}
+
+function handleRequest(request, response) {
+  const { queryString } = request;
+  if (!queryString) {
+    response.processAsync();
+    setResponse(response);
+    response.setHeader("Content-Type", "application/json");
+    // Write something so that the JSON viewer app starts loading.
+    response.write(" ");
+    return;
+  }
+  const [command, value] = queryString.split("=");
+  switch (command) {
+    case "write":
+      getResponse().write(value);
+      break;
+    case "close":
+      getResponse().finish();
+      setResponse(null);
+      break;
+  }
+  response.setHeader("Content-Type", "text/plain");
+  response.write("ok");
+}
diff --git a/devtools/client/jsonview/test/csp_json.json b/devtools/client/jsonview/test/csp_json.json
new file mode 100644
index 0000000000..9fc9368255
--- /dev/null
+++ b/devtools/client/jsonview/test/csp_json.json
@@ -0,0 +1 @@
+{ "csp": true }
diff --git a/devtools/client/jsonview/test/csp_json.json^headers^ b/devtools/client/jsonview/test/csp_json.json^headers^
new file mode 100644
index 0000000000..d6d0a72a4b
--- /dev/null
+++ b/devtools/client/jsonview/test/csp_json.json^headers^
@@ -0,0 +1,2 @@
+Content-Type: application/json
+Content-Security-Policy: default-src 'none'; base-uri 'none';
diff --git a/devtools/client/jsonview/test/empty.html b/devtools/client/jsonview/test/empty.html
new file mode 100644
index 0000000000..c50eddd41f
--- /dev/null
+++ b/devtools/client/jsonview/test/empty.html
@@ -0,0 +1 @@
+<!doctype html>
diff --git a/devtools/client/jsonview/test/head.js b/devtools/client/jsonview/test/head.js
new file mode 100644
index 0000000000..5c9ee85ea2
--- /dev/null
+++ b/devtools/client/jsonview/test/head.js
@@ -0,0 +1,278 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+/* eslint no-unused-vars: [2, {"vars": "local", "args": "none"}] */
+
+"use strict";
+
+// shared-head.js handles imports, constants, and utility functions
+Services.scriptloader.loadSubScript(
+  "chrome://mochitests/content/browser/devtools/client/framework/test/head.js",
+  this
+);
+
+const JSON_VIEW_PREF = "devtools.jsonview.enabled";
+
+// Enable JSON View for the test
+Services.prefs.setBoolPref(JSON_VIEW_PREF, true);
+
+registerCleanupFunction(() => {
+  Services.prefs.clearUserPref(JSON_VIEW_PREF);
+});
+
+// XXX move some API into devtools/shared/test/shared-head.js
+
+/**
+ * Add a new test tab in the browser and load the given url.
+ * @param {String} url
+ *   The url to be loaded in the new tab.
+ *
+ * @param {Object} [optional]
+ *   An object with the following optional properties:
+ *   - appReadyState: The readyState of the JSON Viewer app that you want to
+ *     wait for. Its value can be one of:
+ *      - "uninitialized": The converter has started the request.
+ *        If JavaScript is disabled, there will be no more readyState changes.
+ *      - "loading": RequireJS started loading the scripts for the JSON Viewer.
+ *        If the load timeouts, there will be no more readyState changes.
+ *      - "interactive": The JSON Viewer app loaded, but possibly not all the JSON
+ *        data has been received.
+ *      - "complete" (default): The app is fully loaded with all the JSON.
+ *   - docReadyState: The standard readyState of the document that you want to
+ *     wait for. Its value can be one of:
+ *      - "loading": The JSON data has not been completely loaded (but the app might).
+ *      - "interactive": All the JSON data has been received.
+ *      - "complete" (default): Since there aren't sub-resources like images,
+ *        behaves as "interactive". Note the app might not be loaded yet.
+ */
+async function addJsonViewTab(
+  url,
+  { appReadyState = "complete", docReadyState = "complete" } = {}
+) {
+  info("Adding a new JSON tab with URL: '" + url + "'");
+  const tabAdded = BrowserTestUtils.waitForNewTab(gBrowser, url);
+  const tabLoaded = addTab(url);
+
+  // The `tabAdded` promise resolves when the JSON Viewer starts loading.
+  // This is usually what we want, however, it never resolves for unrecognized
+  // content types that trigger a download.
+  // On the other hand, `tabLoaded` always resolves, but not until the document
+  // is fully loaded, which is too late if `docReadyState !== "complete"`.
+  // Therefore, we race both promises.
+  const tab = await Promise.race([tabAdded, tabLoaded]);
+  const browser = tab.linkedBrowser;
+
+  const rootDir = getRootDirectory(gTestPath);
+
+  // Catch RequireJS errors (usually timeouts)
+  const error = tabLoaded.then(() =>
+    SpecialPowers.spawn(browser, [], function () {
+      return new Promise((resolve, reject) => {
+        const { requirejs } = content.wrappedJSObject;
+        if (requirejs) {
+          requirejs.onError = err => {
+            info(err);
+            ok(false, "RequireJS error");
+            reject(err);
+          };
+        }
+      });
+    })
+  );
+
+  const data = { rootDir, appReadyState, docReadyState };
+  await Promise.race([
+    error,
+    // eslint-disable-next-line no-shadow
+    ContentTask.spawn(browser, data, async function (data) {
+      // Check if there is a JSONView object.
+      const { JSONView } = content.wrappedJSObject;
+      if (!JSONView) {
+        throw new Error("The JSON Viewer did not load.");
+      }
+
+      const docReadyStates = ["loading", "interactive", "complete"];
+      const docReadyIndex = docReadyStates.indexOf(data.docReadyState);
+      const appReadyStates = ["uninitialized", ...docReadyStates];
+      const appReadyIndex = appReadyStates.indexOf(data.appReadyState);
+      if (docReadyIndex < 0 || appReadyIndex < 0) {
+        throw new Error("Invalid app or doc readyState parameter.");
+      }
+
+      // Wait until the document readyState suffices.
+      const { document } = content;
+      while (docReadyStates.indexOf(document.readyState) < docReadyIndex) {
+        info(
+          `DocReadyState is "${document.readyState}". Await "${data.docReadyState}"`
+        );
+        await new Promise(resolve => {
+          document.addEventListener("readystatechange", resolve, {
+            once: true,
+          });
+        });
+      }
+
+      // Wait until the app readyState suffices.
+      while (appReadyStates.indexOf(JSONView.readyState) < appReadyIndex) {
+        info(
+          `AppReadyState is "${JSONView.readyState}". Await "${data.appReadyState}"`
+        );
+        await new Promise(resolve => {
+          content.addEventListener("AppReadyStateChange", resolve, {
+            once: true,
+          });
+        });
+      }
+    }),
+  ]);
+
+  return tab;
+}
+
+/**
+ * Expanding a node in the JSON tree
+ */
+function clickJsonNode(selector) {
+  info("Expanding node: '" + selector + "'");
+
+  // eslint-disable-next-line no-shadow
+  return ContentTask.spawn(gBrowser.selectedBrowser, selector, selector => {
+    content.document.querySelector(selector).click();
+  });
+}
+
+/**
+ * Select JSON View tab (in the content).
+ */
+function selectJsonViewContentTab(name) {
+  info("Selecting tab: '" + name + "'");
+
+  // eslint-disable-next-line no-shadow
+  return ContentTask.spawn(gBrowser.selectedBrowser, name, async name => {
+    const selector = ".tabs-menu .tabs-menu-item." + CSS.escape(name) + " a";
+    const element = content.document.querySelector(selector);
+    is(element.getAttribute("aria-selected"), "false", "Tab not selected yet");
+    await new Promise(resolve => {
+      content.addEventListener("TabChanged", resolve, { once: true });
+      element.click();
+    });
+    is(element.getAttribute("aria-selected"), "true", "Tab is now selected");
+  });
+}
+
+function getElementCount(selector) {
+  info("Get element count: '" + selector + "'");
+
+  return SpecialPowers.spawn(
+    gBrowser.selectedBrowser,
+    [selector],
+    selectorChild => {
+      return content.document.querySelectorAll(selectorChild).length;
+    }
+  );
+}
+
+function getElementText(selector) {
+  info("Get element text: '" + selector + "'");
+
+  return SpecialPowers.spawn(
+    gBrowser.selectedBrowser,
+    [selector],
+    selectorChild => {
+      const element = content.document.querySelector(selectorChild);
+      return element ? element.textContent : null;
+    }
+  );
+}
+
+function getElementAttr(selector, attr) {
+  info("Get attribute '" + attr + "' for element '" + selector + "'");
+
+  return SpecialPowers.spawn(
+    gBrowser.selectedBrowser,
+    [selector, attr],
+    (selectorChild, attrChild) => {
+      const element = content.document.querySelector(selectorChild);
+      return element ? element.getAttribute(attrChild) : null;
+    }
+  );
+}
+
+function focusElement(selector) {
+  info("Focus element: '" + selector + "'");
+
+  return SpecialPowers.spawn(
+    gBrowser.selectedBrowser,
+    [selector],
+    selectorChild => {
+      const element = content.document.querySelector(selectorChild);
+      if (element) {
+        element.focus();
+      }
+    }
+  );
+}
+
+/**
+ * Send the string aStr to the focused element.
+ *
+ * For now this method only works for ASCII characters and emulates the shift
+ * key state on US keyboard layout.
+ */
+function sendString(str, selector) {
+  info("Send string: '" + str + "'");
+
+  return SpecialPowers.spawn(
+    gBrowser.selectedBrowser,
+    [selector, str],
+    (selectorChild, strChild) => {
+      if (selectorChild) {
+        const element = content.document.querySelector(selectorChild);
+        if (element) {
+          element.focus();
+        }
+      }
+
+      EventUtils.sendString(strChild, content);
+    }
+  );
+}
+
+function waitForTime(delay) {
+  return new Promise(resolve => setTimeout(resolve, delay));
+}
+
+function waitForFilter() {
+  return SpecialPowers.spawn(gBrowser.selectedBrowser, [], () => {
+    return new Promise(resolve => {
+      const firstRow = content.document.querySelector(
+        ".jsonPanelBox .treeTable .treeRow"
+      );
+
+      // Check if the filter is already set.
+      if (firstRow.classList.contains("hidden")) {
+        resolve();
+        return;
+      }
+
+      // Wait till the first row has 'hidden' class set.
+      const observer = new content.MutationObserver(function (mutations) {
+        for (let i = 0; i < mutations.length; i++) {
+          const mutation = mutations[i];
+          if (mutation.attributeName == "class") {
+            if (firstRow.classList.contains("hidden")) {
+              observer.disconnect();
+              resolve();
+              break;
+            }
+          }
+        }
+      });
+
+      observer.observe(firstRow, { attributes: true });
+    });
+  });
+}
+
+function normalizeNewLines(value) {
+  return value.replace("(\r\n|\n)", "\n");
+}
diff --git a/devtools/client/jsonview/test/invalid_json.json b/devtools/client/jsonview/test/invalid_json.json
new file mode 100644
index 0000000000..004e1e2032
--- /dev/null
+++ b/devtools/client/jsonview/test/invalid_json.json
@@ -0,0 +1 @@
+{,}
diff --git a/devtools/client/jsonview/test/invalid_json.json^headers^ b/devtools/client/jsonview/test/invalid_json.json^headers^
new file mode 100644
index 0000000000..6010bfd188
--- /dev/null
+++ b/devtools/client/jsonview/test/invalid_json.json^headers^
@@ -0,0 +1 @@
+Content-Type: application/json; charset=utf-8
diff --git a/devtools/client/jsonview/test/manifest_json.json b/devtools/client/jsonview/test/manifest_json.json
new file mode 100644
index 0000000000..b178f7acf4
--- /dev/null
+++ b/devtools/client/jsonview/test/manifest_json.json
@@ -0,0 +1,49 @@
+{
+  "name": "HackerWeb",
+  "short_name": "HackerWeb",
+  "start_url": ".",
+  "display": "standalone",
+  "background_color": "#fff",
+  "description": "A simply readable Hacker News app.",
+  "icons": [
+    {
+      "src": "images/touch/homescreen48.png",
+      "sizes": "48x48",
+      "type": "image/png"
+    },
+    {
+      "src": "images/touch/homescreen72.png",
+      "sizes": "72x72",
+      "type": "image/png"
+    },
+    {
+      "src": "images/touch/homescreen96.png",
+      "sizes": "96x96",
+      "type": "image/png"
+    },
+    {
+      "src": "images/touch/homescreen144.png",
+      "sizes": "144x144",
+      "type": "image/png"
+    },
+    {
+      "src": "images/touch/homescreen168.png",
+      "sizes": "168x168",
+      "type": "image/png"
+    },
+    {
+      "src": "images/touch/homescreen192.png",
+      "sizes": "192x192",
+      "type": "image/png"
+    }
+  ],
+  "related_applications": [
+    {
+      "platform": "web"
+    },
+    {
+      "platform": "play",
+      "url": "https://play.google.com/store/apps/details?id=cheeaun.hackerweb"
+    }
+  ]
+}
diff --git a/devtools/client/jsonview/test/manifest_json.json^headers^ b/devtools/client/jsonview/test/manifest_json.json^headers^
new file mode 100644
index 0000000000..2bab061d43
--- /dev/null
+++ b/devtools/client/jsonview/test/manifest_json.json^headers^
@@ -0,0 +1 @@
+Content-Type: application/manifest+json; charset=utf-8
diff --git a/devtools/client/jsonview/test/passthrough-sw.js b/devtools/client/jsonview/test/passthrough-sw.js
new file mode 100644
index 0000000000..019d218bc2
--- /dev/null
+++ b/devtools/client/jsonview/test/passthrough-sw.js
@@ -0,0 +1,5 @@
+"use strict";
+
+addEventListener("fetch", evt => {
+  evt.respondWith(fetch(evt.request));
+});
diff --git a/devtools/client/jsonview/test/simple_json.json b/devtools/client/jsonview/test/simple_json.json
new file mode 100644
index 0000000000..d1544242f5
--- /dev/null
+++ b/devtools/client/jsonview/test/simple_json.json
@@ -0,0 +1 @@
+{ "name": "value" }
diff --git a/devtools/client/jsonview/test/simple_json.json^headers^ b/devtools/client/jsonview/test/simple_json.json^headers^
new file mode 100644
index 0000000000..6010bfd188
--- /dev/null
+++ b/devtools/client/jsonview/test/simple_json.json^headers^
@@ -0,0 +1 @@
+Content-Type: application/json; charset=utf-8
diff --git a/devtools/client/jsonview/test/valid_json.json b/devtools/client/jsonview/test/valid_json.json
new file mode 100644
index 0000000000..ca7356ccdb
--- /dev/null
+++ b/devtools/client/jsonview/test/valid_json.json
@@ -0,0 +1,6 @@
+{
+  "family": {
+    "father": "John Doe",
+    "mother": "Alice Doe"
+  }
+}
diff --git a/devtools/client/jsonview/test/valid_json.json^headers^ b/devtools/client/jsonview/test/valid_json.json^headers^
new file mode 100644
index 0000000000..6010bfd188
--- /dev/null
+++ b/devtools/client/jsonview/test/valid_json.json^headers^
@@ -0,0 +1 @@
+Content-Type: application/json; charset=utf-8
diff --git a/devtools/client/jsonview/viewer-config.js b/devtools/client/jsonview/viewer-config.js
new file mode 100644
index 0000000000..6ab0de0a8f
--- /dev/null
+++ b/devtools/client/jsonview/viewer-config.js
@@ -0,0 +1,46 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+/* global requirejs */
+
+"use strict";
+
+// Send readyState change notification event to the window. It's useful for tests.
+JSONView.readyState = "loading";
+window.dispatchEvent(new CustomEvent("AppReadyStateChange"));
+
+// Services is required in the Reps bundle but can't be loaded in the json-viewer.
+// Since it's only used for the ObjectInspector, that the json-viewer does not use, we
+// can mock it. The mock should be removed when we un-bundle reps, (i.e. land individual
+// files instead of a big bundle).
+define("ServicesMock", () => ({ appinfo: {} }));
+// custom-formatter is required in the Reps bundle but 1. we don't need in the JSON Viewer,
+// and 2. it causes issues as this requires the ObjectInspector, which can't be loaded
+// via requirejs.
+define("CustomFormatterMock", () => ({}));
+
+/**
+ * RequireJS configuration for JSON Viewer.
+ *
+ * React module ID is using exactly the same (relative) path as the rest
+ * of the code base, so it's consistent and modules can be easily reused.
+ */
+require.config({
+  baseUrl: "resource://devtools-client-jsonview/",
+  paths: {
+    "devtools/client/jsonview": "resource://devtools-client-jsonview",
+    "devtools/client/shared": "resource://devtools-client-shared",
+    "devtools/shared": "resource://devtools/shared",
+    Services: "resource://devtools-client-shared/vendor/react-prop-types",
+  },
+  map: {
+    "*": {
+      Services: "ServicesMock",
+      "devtools/client/shared/components/reps/reps/custom-formatter":
+        "CustomFormatterMock",
+    },
+  },
+});
+
+// Load the main panel module
+requirejs(["json-viewer"]);