Adding upstream version 1.55.0+dfsg.upstream/1.55.0+dfsg

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

15 files changed, 3869 insertions, 0 deletions

diff --git a/src/js/scriptlets/cosmetic-logger.js b/src/js/scriptlets/cosmetic-logger.js
new file mode 100644
index 0000000..5d1f1b9
--- /dev/null
+++ b/src/js/scriptlets/cosmetic-logger.js
@@ -0,0 +1,365 @@
+/*******************************************************************************
+
+    uBlock Origin - a comprehensive, efficient content blocker
+    Copyright (C) 2015-present Raymond Hill
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see {http://www.gnu.org/licenses/}.
+
+    Home: https://github.com/gorhill/uBlock
+*/
+
+/* globals browser */
+
+'use strict';
+
+/******************************************************************************/
+
+(( ) => {
+// >>>>>>>> start of private namespace
+
+/******************************************************************************/
+
+if ( typeof vAPI !== 'object' ) { return; }
+if ( vAPI.domWatcher instanceof Object === false ) { return; }
+
+const reHasCSSCombinators = /[ >+~]/;
+const simpleDeclarativeSet = new Set();
+let simpleDeclarativeStr;
+const complexDeclarativeSet = new Set();
+let complexDeclarativeStr;
+const proceduralDict = new Map();
+const exceptionDict = new Map();
+let exceptionStr;
+const proceduralExceptionDict = new Map();
+const nodesToProcess = new Set();
+const loggedSelectors = new Set();
+
+/******************************************************************************/
+
+const rePseudoElements = /:(?::?after|:?before|:[a-z-]+)$/;
+
+function hasSelector(selector, context = document) {
+    try {
+        return context.querySelector(selector) !== null;
+    }
+    catch(ex) {
+    }
+    return false;
+}
+
+function safeMatchSelector(selector, context) {
+    const safeSelector = rePseudoElements.test(selector)
+        ? selector.replace(rePseudoElements, '')
+        : selector;
+    try {
+        return context.matches(safeSelector);
+    }
+    catch(ex) {
+    }
+    return false;
+}
+
+function safeQuerySelector(selector, context = document) {
+    const safeSelector = rePseudoElements.test(selector)
+        ? selector.replace(rePseudoElements, '')
+        : selector;
+    try {
+        return context.querySelector(safeSelector);
+    }
+    catch(ex) {
+    }
+    return null;
+}
+
+function safeGroupSelectors(selectors) {
+    const arr = Array.isArray(selectors)
+        ? selectors
+        : Array.from(selectors);
+    return arr.map(s => {
+        return rePseudoElements.test(s)
+            ? s.replace(rePseudoElements, '')
+            : s;
+    }).join(',\n');
+}
+
+/******************************************************************************/
+
+function processDeclarativeSimple(node, out) {
+    if ( simpleDeclarativeSet.size === 0 ) { return; }
+    if ( simpleDeclarativeStr === undefined ) {
+        simpleDeclarativeStr = safeGroupSelectors(simpleDeclarativeSet);
+    }
+    if (
+        (node === document || node.matches(simpleDeclarativeStr) === false) &&
+        (hasSelector(simpleDeclarativeStr, node) === false)
+    ) {
+        return;
+    }
+    for ( const selector of simpleDeclarativeSet ) {
+        if (
+            (node === document || safeMatchSelector(selector, node) === false) &&
+            (safeQuerySelector(selector, node) === null)
+        ) {
+            continue;
+        }
+        out.push(`##${selector}`);
+        simpleDeclarativeSet.delete(selector);
+        simpleDeclarativeStr = undefined;
+        loggedSelectors.add(selector);
+    }
+}
+
+/******************************************************************************/
+
+function processDeclarativeComplex(out) {
+    if ( complexDeclarativeSet.size === 0 ) { return; }
+    if ( complexDeclarativeStr === undefined ) {
+        complexDeclarativeStr = safeGroupSelectors(complexDeclarativeSet);
+    }
+    if ( hasSelector(complexDeclarativeStr) === false ) { return; }
+    for ( const selector of complexDeclarativeSet ) {
+        if ( safeQuerySelector(selector) === null ) { continue; }
+        out.push(`##${selector}`);
+        complexDeclarativeSet.delete(selector);
+        complexDeclarativeStr = undefined;
+        loggedSelectors.add(selector);
+    }
+}
+
+/******************************************************************************/
+
+function processProcedural(out) {
+    if ( proceduralDict.size === 0 ) { return; }
+    for ( const [ raw, pselector ] of proceduralDict ) {
+        if ( pselector.converted ) {
+            if ( safeQuerySelector(pselector.selector) === null ) { continue; }
+        } else if ( pselector.hit === false && pselector.exec().length === 0 ) {
+            continue;
+        }
+        out.push(`##${raw}`);
+        proceduralDict.delete(raw);
+    }
+}
+
+/******************************************************************************/
+
+function processExceptions(out) {
+    if ( exceptionDict.size === 0 ) { return; }
+    if ( exceptionStr === undefined ) {
+        exceptionStr = safeGroupSelectors(exceptionDict.keys());
+    }
+    if ( hasSelector(exceptionStr) === false ) { return; }
+    for ( const [ selector, raw ] of exceptionDict ) {
+        if ( safeQuerySelector(selector) === null ) { continue; }
+        out.push(`#@#${raw}`);
+        exceptionDict.delete(selector);
+        exceptionStr = undefined;
+        loggedSelectors.add(raw);
+    }
+}
+
+/******************************************************************************/
+
+function processProceduralExceptions(out) {
+    if ( proceduralExceptionDict.size === 0 ) { return; }
+    for ( const exception of proceduralExceptionDict.values() ) {
+        if ( exception.test() === false ) { continue; }
+        out.push(`#@#${exception.raw}`);
+        proceduralExceptionDict.delete(exception.raw);
+    }
+}
+
+/******************************************************************************/
+
+const processTimer = new vAPI.SafeAnimationFrame(( ) => {
+    //console.time('dom logger/scanning for matches');
+    processTimer.clear();
+    if ( nodesToProcess.size === 0 ) { return; }
+
+    if ( nodesToProcess.size !== 1 && nodesToProcess.has(document) ) {
+        nodesToProcess.clear();
+        nodesToProcess.add(document);
+    }
+
+    const toLog = [];
+    if ( simpleDeclarativeSet.size !== 0 ) {
+        for ( const node of nodesToProcess ) {
+            processDeclarativeSimple(node, toLog);
+        }
+    }
+
+    processDeclarativeComplex(toLog);
+    processProcedural(toLog);
+    processExceptions(toLog);
+    processProceduralExceptions(toLog);
+
+    nodesToProcess.clear();
+
+    if ( toLog.length === 0 ) { return; }
+
+    const location = vAPI.effectiveSelf.location;
+
+    vAPI.messaging.send('scriptlets', {
+        what: 'logCosmeticFilteringData',
+        frameURL: location.href,
+        frameHostname: location.hostname,
+        matchedSelectors: toLog,
+    });
+    //console.timeEnd('dom logger/scanning for matches');
+});
+
+/******************************************************************************/
+
+const attributeObserver = new MutationObserver(mutations => {
+    if ( nodesToProcess.has(document) ) { return; }
+    for ( const mutation of mutations ) {
+        const node = mutation.target;
+        if ( node.nodeType !== 1 ) { continue; }
+        nodesToProcess.add(node);
+    }
+    if ( nodesToProcess.size !== 0 ) {
+        processTimer.start(100);
+    }
+});
+
+/******************************************************************************/
+
+const handlers = {
+    onFiltersetChanged: function(changes) {
+        //console.time('dom logger/filterset changed');
+        for ( const block of (changes.declarative || []) ) {
+            for ( const selector of block.split(',\n') ) {
+                if ( loggedSelectors.has(selector) ) { continue; }
+                if ( reHasCSSCombinators.test(selector) ) {
+                    complexDeclarativeSet.add(selector);
+                    complexDeclarativeStr = undefined;
+                } else {
+                    simpleDeclarativeSet.add(selector);
+                    simpleDeclarativeStr = undefined;
+                }
+            }
+        }
+        if (
+            Array.isArray(changes.procedural) &&
+            changes.procedural.length !== 0
+        ) {
+            for ( const selector of changes.procedural ) {
+                proceduralDict.set(selector.raw, selector);
+            }
+        }
+        if ( Array.isArray(changes.exceptions) ) {
+            for ( const selector of changes.exceptions ) {
+                if ( loggedSelectors.has(selector) ) { continue; }
+                if ( selector.charCodeAt(0) !== 0x7B /* '{' */ ) {
+                    exceptionDict.set(selector, selector);
+                    continue;
+                }
+                const details = JSON.parse(selector);
+                if (
+                    details.action !== undefined &&
+                    details.tasks === undefined &&
+                    details.action[0] === 'style'
+                ) {
+                    exceptionDict.set(details.selector, details.raw);
+                    continue;
+                }
+                proceduralExceptionDict.set(
+                    details.raw,
+                    vAPI.domFilterer.createProceduralFilter(details)
+                );
+            }
+            exceptionStr = undefined;
+        }
+        nodesToProcess.clear();
+        nodesToProcess.add(document);
+        processTimer.start(1);
+        //console.timeEnd('dom logger/filterset changed');
+    },
+
+    onDOMCreated: function() {
+        if ( vAPI.domFilterer instanceof Object === false ) {
+            return shutdown();
+        }
+        handlers.onFiltersetChanged(vAPI.domFilterer.getAllSelectors());
+        vAPI.domFilterer.addListener(handlers);
+        attributeObserver.observe(document.body, {
+            attributes: true,
+            subtree: true
+        });
+    },
+
+    onDOMChanged: function(addedNodes) {
+        if ( nodesToProcess.has(document) ) { return; }
+        for ( const node of addedNodes ) {
+            if ( node.parentNode === null ) { continue; }
+            nodesToProcess.add(node);
+        }
+        if ( nodesToProcess.size !== 0 ) {
+            processTimer.start(100);
+        }
+    }
+};
+
+vAPI.domWatcher.addListener(handlers);
+
+/******************************************************************************/
+
+const broadcastHandler = msg => {
+    if ( msg.what === 'loggerDisabled' ) {
+        shutdown();
+    }
+};
+
+browser.runtime.onMessage.addListener(broadcastHandler);
+
+/******************************************************************************/
+
+function shutdown() {
+    browser.runtime.onMessage.removeListener(broadcastHandler);
+    processTimer.clear();
+    attributeObserver.disconnect();
+    if ( typeof vAPI !== 'object' ) { return; }
+    if ( vAPI.domFilterer instanceof Object ) {
+        vAPI.domFilterer.removeListener(handlers);
+    }
+    if ( vAPI.domWatcher instanceof Object ) {
+        vAPI.domWatcher.removeListener(handlers);
+    }
+}
+
+/******************************************************************************/
+
+// <<<<<<<< end of private namespace
+})();
+
+
+
+
+
+
+
+
+/*******************************************************************************
+
+    DO NOT:
+    - Remove the following code
+    - Add code beyond the following code
+    Reason:
+    - https://github.com/gorhill/uBlock/pull/3721
+    - uBO never uses the return value from injected content scripts
+
+**/
+
+void 0;
+
diff --git a/src/js/scriptlets/cosmetic-off.js b/src/js/scriptlets/cosmetic-off.js
new file mode 100644
index 0000000..f1301e2
--- /dev/null
+++ b/src/js/scriptlets/cosmetic-off.js
@@ -0,0 +1,48 @@
+/*******************************************************************************
+
+    uBlock Origin - a comprehensive, efficient content blocker
+    Copyright (C) 2015-2018 Raymond Hill
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see {http://www.gnu.org/licenses/}.
+
+    Home: https://github.com/gorhill/uBlock
+*/
+
+'use strict';
+
+/******************************************************************************/
+
+if ( typeof vAPI === 'object' && vAPI.domFilterer ) {
+    vAPI.domFilterer.toggle(false);
+}
+
+
+
+
+
+
+
+
+/*******************************************************************************
+
+    DO NOT:
+    - Remove the following code
+    - Add code beyond the following code
+    Reason:
+    - https://github.com/gorhill/uBlock/pull/3721
+    - uBO never uses the return value from injected content scripts
+
+**/
+
+void 0;
diff --git a/src/js/scriptlets/cosmetic-on.js b/src/js/scriptlets/cosmetic-on.js
new file mode 100644
index 0000000..7b30976
--- /dev/null
+++ b/src/js/scriptlets/cosmetic-on.js
@@ -0,0 +1,48 @@
+/*******************************************************************************
+
+    uBlock Origin - a comprehensive, efficient content blocker
+    Copyright (C) 2015-2018 Raymond Hill
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see {http://www.gnu.org/licenses/}.
+
+    Home: https://github.com/gorhill/uBlock
+*/
+
+'use strict';
+
+/******************************************************************************/
+
+if ( typeof vAPI === 'object' && vAPI.domFilterer ) {
+    vAPI.domFilterer.toggle(true);
+}
+
+
+
+
+
+
+
+
+/*******************************************************************************
+
+    DO NOT:
+    - Remove the following code
+    - Add code beyond the following code
+    Reason:
+    - https://github.com/gorhill/uBlock/pull/3721
+    - uBO never uses the return value from injected content scripts
+
+**/
+
+void 0;
diff --git a/src/js/scriptlets/cosmetic-report.js b/src/js/scriptlets/cosmetic-report.js
new file mode 100644
index 0000000..a968d4d
--- /dev/null
+++ b/src/js/scriptlets/cosmetic-report.js
@@ -0,0 +1,142 @@
+/*******************************************************************************
+
+    uBlock Origin - a comprehensive, efficient content blocker
+    Copyright (C) 2015-present Raymond Hill
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see {http://www.gnu.org/licenses/}.
+
+    Home: https://github.com/gorhill/uBlock
+*/
+
+'use strict';
+
+/******************************************************************************/
+
+(( ) => {
+// >>>>>>>> start of private namespace
+
+/******************************************************************************/
+
+if ( typeof vAPI !== 'object' ) { return; }
+if ( typeof vAPI.domFilterer !== 'object' ) { return; }
+if ( vAPI.domFilterer === null ) { return; }
+
+/******************************************************************************/
+
+const rePseudoElements = /:(?::?after|:?before|:[a-z-]+)$/;
+
+const hasSelector = selector => {
+    try {
+        return document.querySelector(selector) !== null;
+    }
+    catch(ex) {
+    }
+    return false;
+};
+
+const safeQuerySelector = selector => {
+    const safeSelector = rePseudoElements.test(selector)
+        ? selector.replace(rePseudoElements, '')
+        : selector;
+    try {
+        return document.querySelector(safeSelector);
+    }
+    catch(ex) {
+    }
+    return null;
+};
+
+const safeGroupSelectors = selectors => {
+    const arr = Array.isArray(selectors)
+        ? selectors
+        : Array.from(selectors);
+    return arr.map(s => {
+        return rePseudoElements.test(s)
+            ? s.replace(rePseudoElements, '')
+            : s;
+    }).join(',\n');
+};
+
+const allSelectors = vAPI.domFilterer.getAllSelectors();
+const matchedSelectors = [];
+
+if ( Array.isArray(allSelectors.declarative) ) {
+    const declarativeSet = new Set();
+    for ( const block of allSelectors.declarative ) {
+        for ( const selector of block.split(',\n') ) {
+            declarativeSet.add(selector);
+        }
+    }
+    if ( hasSelector(safeGroupSelectors(declarativeSet)) ) {
+        for ( const selector of declarativeSet ) {
+            if ( safeQuerySelector(selector) === null ) { continue; }
+            matchedSelectors.push(`##${selector}`);
+        }
+    }
+}
+
+if (
+    Array.isArray(allSelectors.procedural) &&
+    allSelectors.procedural.length !== 0
+) {
+    for ( const pselector of allSelectors.procedural ) {
+        if ( pselector.hit === false && pselector.exec().length === 0 ) { continue; }
+        matchedSelectors.push(`##${pselector.raw}`);
+    }
+}
+
+if ( Array.isArray(allSelectors.exceptions) ) {
+    const exceptionDict = new Map();
+    for ( const selector of allSelectors.exceptions ) {
+        if ( selector.charCodeAt(0) !== 0x7B /* '{' */ ) {
+            exceptionDict.set(selector, selector);
+            continue;
+        }
+        const details = JSON.parse(selector);
+        if (
+            details.action !== undefined &&
+            details.tasks === undefined &&
+            details.action[0] === 'style'
+        ) {
+            exceptionDict.set(details.selector, details.raw);
+            continue;
+        }
+        const pselector = vAPI.domFilterer.createProceduralFilter(details);
+        if ( pselector.test() === false ) { continue; }
+        matchedSelectors.push(`#@#${pselector.raw}`);
+    }
+    if (
+        exceptionDict.size !== 0 &&
+        hasSelector(safeGroupSelectors(exceptionDict.keys()))
+    ) {
+        for ( const [ selector, raw ] of exceptionDict ) {
+            if ( safeQuerySelector(selector) === null ) { continue; }
+            matchedSelectors.push(`#@#${raw}`);
+        }
+    }
+}
+
+if ( typeof self.uBO_scriptletsInjected === 'string' ) {
+    matchedSelectors.push(...self.uBO_scriptletsInjected.split('\n'));
+}
+
+if ( matchedSelectors.length === 0 ) { return; }
+
+return matchedSelectors;
+
+/******************************************************************************/
+
+// <<<<<<<< end of private namespace
+})();
+
diff --git a/src/js/scriptlets/dom-inspector.js b/src/js/scriptlets/dom-inspector.js
new file mode 100644
index 0000000..b5317d5
--- /dev/null
+++ b/src/js/scriptlets/dom-inspector.js
@@ -0,0 +1,924 @@
+/*******************************************************************************
+
+    uBlock Origin - a comprehensive, efficient content blocker
+    Copyright (C) 2015-present Raymond Hill
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see {http://www.gnu.org/licenses/}.
+
+    Home: https://github.com/gorhill/uBlock
+*/
+
+/* globals browser */
+
+'use strict';
+
+/******************************************************************************/
+/******************************************************************************/
+
+(async ( ) => {
+
+/******************************************************************************/
+
+if ( typeof vAPI !== 'object' ) { return; }
+if ( typeof vAPI === null ) { return; }
+if ( vAPI.domFilterer instanceof Object === false ) { return; }
+
+if ( vAPI.inspectorFrame ) { return; }
+vAPI.inspectorFrame = true;
+
+const inspectorUniqueId = vAPI.randomToken();
+
+const nodeToIdMap = new WeakMap(); // No need to iterate
+
+let blueNodes = [];
+const roRedNodes = new Map();    // node => current cosmetic filter
+const rwRedNodes = new Set();    // node => new cosmetic filter (toggle node)
+const rwGreenNodes = new Set();  // node => new exception cosmetic filter (toggle filter)
+//const roGreenNodes = new Map();  // node => current exception cosmetic filter (can't toggle)
+
+const reHasCSSCombinators = /[ >+~]/;
+
+/******************************************************************************/
+
+const domLayout = (( ) => {
+    const skipTagNames = new Set([
+        'br', 'head', 'link', 'meta', 'script', 'style', 'title'
+    ]);
+    const resourceAttrNames = new Map([
+        [ 'a', 'href' ],
+        [ 'iframe', 'src' ],
+        [ 'img', 'src' ],
+        [ 'object', 'data' ]
+    ]);
+
+    let idGenerator = 1;
+
+    // This will be used to uniquely identify nodes across process.
+
+    const newNodeId = node => {
+        const nid = `n${(idGenerator++).toString(36)}`;
+        nodeToIdMap.set(node, nid);
+        return nid;
+    };
+
+    const selectorFromNode = node => {
+        const tag = node.localName;
+        let selector = CSS.escape(tag);
+        // Id
+        if ( typeof node.id === 'string' ) {
+            let str = node.id.trim();
+            if ( str !== '' ) {
+                selector += `#${CSS.escape(str)}`;
+            }
+        }
+        // Class
+        const cl = node.classList;
+        if ( cl ) {
+            for ( let i = 0; i < cl.length; i++ ) {
+                selector += `.${CSS.escape(cl[i])}`;
+            }
+        }
+        // Tag-specific attributes
+        const attr = resourceAttrNames.get(tag);
+        if ( attr !== undefined ) {
+            let str = node.getAttribute(attr) || '';
+            str = str.trim();
+            const pos = str.startsWith('data:') ? 5 : str.search(/[#?]/);
+            let sw = '';
+            if ( pos !== -1 ) {
+                str = str.slice(0, pos);
+                sw = '^';
+            }
+            if ( str !== '' ) {
+                selector += `[${attr}${sw}="${CSS.escape(str, true)}"]`;
+            }
+        }
+        return selector;
+    };
+
+    function DomRoot() {
+        this.nid = newNodeId(document.body);
+        this.lvl = 0;
+        this.sel = 'body';
+        this.cnt = 0;
+        this.filter = roRedNodes.get(document.body);
+    }
+
+    function DomNode(node, level) {
+        this.nid = newNodeId(node);
+        this.lvl = level;
+        this.sel = selectorFromNode(node);
+        this.cnt = 0;
+        this.filter = roRedNodes.get(node);
+    }
+
+    const domNodeFactory = (level, node) => {
+        const localName = node.localName;
+        if ( skipTagNames.has(localName) ) { return null; }
+        // skip uBlock's own nodes
+        if ( node === inspectorFrame ) { return null; }
+        if ( level === 0 && localName === 'body' ) {
+            return new DomRoot();
+        }
+        return new DomNode(node, level);
+    };
+
+    // Collect layout data
+
+    const getLayoutData = ( ) => {
+        const layout = [];
+        const stack = [];
+        let lvl = 0;
+        let node = document.documentElement;
+        if ( node === null ) { return layout; }
+
+        for (;;) {
+            const domNode = domNodeFactory(lvl, node);
+            if ( domNode !== null ) {
+                layout.push(domNode);
+            }
+            // children
+            if ( domNode !== null && node.firstElementChild !== null ) {
+                stack.push(node);
+                lvl += 1;
+                node = node.firstElementChild;
+                continue;
+            }
+            // sibling
+            if ( node instanceof Element ) {
+                if ( node.nextElementSibling === null ) {
+                    do {
+                        node = stack.pop();
+                        if ( !node ) { break; }
+                        lvl -= 1;
+                    } while ( node.nextElementSibling === null );
+                    if ( !node ) { break; }
+                }
+                node = node.nextElementSibling;
+            }
+        }
+
+        return layout;
+    };
+
+    // Descendant count for each node.
+
+    const patchLayoutData = layout => {
+        const stack = [];
+        let ptr;
+        let lvl = 0;
+        let i = layout.length;
+
+        while ( i-- ) {
+            const domNode = layout[i];
+            if ( domNode.lvl === lvl ) {
+                stack[ptr] += 1;
+                continue;
+            }
+            if ( domNode.lvl > lvl ) {
+                while ( lvl < domNode.lvl ) {
+                    stack.push(0);
+                    lvl += 1;
+                }
+                ptr = lvl - 1;
+                stack[ptr] += 1;
+                continue;
+            }
+            // domNode.lvl < lvl
+            const cnt = stack.pop();
+            domNode.cnt = cnt;
+            lvl -= 1;
+            ptr = lvl - 1;
+            stack[ptr] += cnt + 1;
+        }
+        return layout;
+    };
+
+    // Track and report mutations of the DOM
+
+    let mutationObserver = null;
+    let mutationTimer;
+    let addedNodelists = [];
+    let removedNodelist = [];
+
+    const previousElementSiblingId = node => {
+        let sibling = node;
+        for (;;) {
+            sibling = sibling.previousElementSibling;
+            if ( sibling === null ) { return null; }
+            if ( skipTagNames.has(sibling.localName) ) { continue; }
+            return nodeToIdMap.get(sibling);
+        }
+    };
+
+    const journalFromBranch = (root, newNodes, newNodeToIdMap) => {
+        let node = root.firstElementChild;
+        while ( node !== null ) {
+            const domNode = domNodeFactory(undefined, node);
+            if ( domNode !== null ) {
+                newNodeToIdMap.set(domNode.nid, domNode);
+                newNodes.push(node);
+            }
+            // down
+            if ( node.firstElementChild !== null ) {
+                node = node.firstElementChild;
+                continue;
+            }
+            // right
+            if ( node.nextElementSibling !== null ) {
+                node = node.nextElementSibling;
+                continue;
+            }
+            // up then right
+            for (;;) {
+                if ( node.parentElement === root ) { return; }
+                node = node.parentElement;
+                if ( node.nextElementSibling !== null ) {
+                    node = node.nextElementSibling;
+                    break;
+                }
+            }
+        }
+    };
+
+    const journalFromMutations = ( ) => {
+        mutationTimer = undefined;
+
+        // This is used to temporarily hold all added nodes, before resolving
+        // their node id and relative position.
+        const newNodes = [];
+        const journalEntries = [];
+        const newNodeToIdMap = new Map();
+
+        for ( const nodelist of addedNodelists ) {
+            for ( const node of nodelist ) {
+                if ( node.nodeType !== 1 ) { continue; }
+                if ( node.parentElement === null ) { continue; }
+                cosmeticFilterMapper.incremental(node);
+                const domNode = domNodeFactory(undefined, node);
+                if ( domNode !== null ) {
+                    newNodeToIdMap.set(domNode.nid, domNode);
+                    newNodes.push(node);
+                }
+                journalFromBranch(node, newNodes, newNodeToIdMap);
+            }
+        }
+        addedNodelists = [];
+        for ( const nodelist of removedNodelist ) {
+            for ( const node of nodelist ) {
+                if ( node.nodeType !== 1 ) { continue; }
+                const nid = nodeToIdMap.get(node);
+                if ( nid === undefined ) { continue; }
+                journalEntries.push({ what: -1, nid });
+            }
+        }
+        removedNodelist = [];
+        for ( const node of newNodes ) {
+            journalEntries.push({
+                what: 1,
+                nid: nodeToIdMap.get(node),
+                u: nodeToIdMap.get(node.parentElement),
+                l: previousElementSiblingId(node)
+            });
+        }
+
+        if ( journalEntries.length === 0 ) { return; }
+
+        contentInspectorChannel.toLogger({
+            what: 'domLayoutIncremental',
+            url: window.location.href,
+            hostname: window.location.hostname,
+            journal: journalEntries,
+            nodes: Array.from(newNodeToIdMap)
+        });
+    };
+
+    const onMutationObserved = mutationRecords => {
+        for ( const record of mutationRecords ) {
+            if ( record.addedNodes.length !== 0 ) {
+                addedNodelists.push(record.addedNodes);
+            }
+            if ( record.removedNodes.length !== 0 ) {
+                removedNodelist.push(record.removedNodes);
+            }
+        }
+        if ( mutationTimer === undefined ) {
+            mutationTimer = vAPI.setTimeout(journalFromMutations, 1000);
+        }
+    };
+
+    // API
+
+    const getLayout = ( ) => {
+        cosmeticFilterMapper.reset();
+        mutationObserver = new MutationObserver(onMutationObserved);
+        mutationObserver.observe(document.body, {
+            childList: true,
+            subtree: true
+        });
+
+        return {
+            what: 'domLayoutFull',
+            url: window.location.href,
+            hostname: window.location.hostname,
+            layout: patchLayoutData(getLayoutData())
+        };
+    };
+
+    const reset = ( ) => {
+        shutdown();
+    };
+
+    const shutdown = ( ) => {
+        if ( mutationTimer !== undefined ) {
+            clearTimeout(mutationTimer);
+            mutationTimer = undefined;
+        }
+        if ( mutationObserver !== null ) {
+            mutationObserver.disconnect();
+            mutationObserver = null;
+        }
+        addedNodelists = [];
+        removedNodelist = [];
+    };
+
+    return {
+        get: getLayout,
+        reset,
+        shutdown,
+    };
+})();
+
+/******************************************************************************/
+/******************************************************************************/
+
+const cosmeticFilterMapper = (( ) => {
+    const nodesFromStyleTag = rootNode => {
+        const filterMap = roRedNodes;
+        const details = vAPI.domFilterer.getAllSelectors();
+
+        // Declarative selectors.
+        for ( const block of (details.declarative || []) ) {
+            for ( const selector of block.split(',\n') ) {
+                let nodes;
+                if ( reHasCSSCombinators.test(selector) ) {
+                    nodes = document.querySelectorAll(selector);
+                } else {
+                    if (
+                        filterMap.has(rootNode) === false &&
+                        rootNode.matches(selector)
+                    ) {
+                        filterMap.set(rootNode, selector);
+                    }
+                    nodes = rootNode.querySelectorAll(selector);
+                }
+                for ( const node of nodes ) {
+                    if ( filterMap.has(node) ) { continue; }
+                    filterMap.set(node, selector);
+                }
+            }
+        }
+
+        // Procedural selectors.
+        for ( const entry of (details.procedural || []) ) {
+            const nodes = entry.exec();
+            for ( const node of nodes ) {
+                // Upgrade declarative selector to procedural one
+                filterMap.set(node, entry.raw);
+            }
+        }
+    };
+
+    const incremental = rootNode => {
+        nodesFromStyleTag(rootNode);
+    };
+
+    const reset = ( ) => {
+        roRedNodes.clear();
+        if ( document.documentElement !== null ) {
+            incremental(document.documentElement);
+        }
+    };
+
+    const shutdown = ( ) => {
+        vAPI.domFilterer.toggle(true);
+    };
+
+    return {
+        incremental,
+        reset,
+        shutdown,
+    };
+})();
+
+/******************************************************************************/
+
+const elementsFromSelector = function(selector, context) {
+    if ( !context ) {
+        context = document;
+    }
+    if ( selector.indexOf(':') !== -1 ) {
+        const out = elementsFromSpecialSelector(selector);
+        if ( out !== undefined ) { return out; }
+    }
+    // plain CSS selector
+    try {
+        return context.querySelectorAll(selector);
+    } catch (ex) {
+    }
+    return [];
+};
+
+const elementsFromSpecialSelector = function(selector) {
+    const out = [];
+    let matches = /^(.+?):has\((.+?)\)$/.exec(selector);
+    if ( matches !== null ) {
+        let nodes;
+        try {
+            nodes = document.querySelectorAll(matches[1]);
+        } catch(ex) {
+            nodes = [];
+        }
+        for ( const node of nodes ) {
+            if ( node.querySelector(matches[2]) === null ) { continue; }
+            out.push(node);
+        }
+        return out;
+    }
+
+    matches = /^:xpath\((.+?)\)$/.exec(selector);
+    if ( matches === null ) { return; }
+    const xpr = document.evaluate(
+        matches[1],
+        document,
+        null,
+        XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE,
+        null
+    );
+    let i = xpr.snapshotLength;
+    while ( i-- ) {
+        out.push(xpr.snapshotItem(i));
+    }
+    return out;
+};
+
+/******************************************************************************/
+
+const highlightElements = ( ) => {
+    const paths = [];
+
+    const path = [];
+    for ( const elem of rwRedNodes.keys() ) {
+        if ( elem === inspectorFrame ) { continue; }
+        if ( rwGreenNodes.has(elem) ) { continue; }
+        if ( typeof elem.getBoundingClientRect !== 'function' ) { continue; }
+        const rect = elem.getBoundingClientRect();
+        const xl = rect.left;
+        const w = rect.width;
+        const yt = rect.top;
+        const h = rect.height;
+        const ws = w.toFixed(1);
+        const poly = 'M' + xl.toFixed(1) + ' ' + yt.toFixed(1) +
+               'h' + ws +
+               'v' + h.toFixed(1) +
+               'h-' + ws +
+               'z';
+        path.push(poly);
+    }
+    paths.push(path.join('') || 'M0 0');
+
+    path.length = 0;
+    for ( const elem of rwGreenNodes ) {
+        if ( typeof elem.getBoundingClientRect !== 'function' ) { continue; }
+        const rect = elem.getBoundingClientRect();
+        const xl = rect.left;
+        const w = rect.width;
+        const yt = rect.top;
+        const h = rect.height;
+        const ws = w.toFixed(1);
+        const poly = 'M' + xl.toFixed(1) + ' ' + yt.toFixed(1) +
+               'h' + ws +
+               'v' + h.toFixed(1) +
+               'h-' + ws +
+               'z';
+        path.push(poly);
+    }
+    paths.push(path.join('') || 'M0 0');
+
+    path.length = 0;
+    for ( const elem of roRedNodes.keys() ) {
+        if ( elem === inspectorFrame ) { continue; }
+        if ( rwGreenNodes.has(elem) ) { continue; }
+        if ( typeof elem.getBoundingClientRect !== 'function' ) { continue; }
+        const rect = elem.getBoundingClientRect();
+        const xl = rect.left;
+        const w = rect.width;
+        const yt = rect.top;
+        const h = rect.height;
+        const ws = w.toFixed(1);
+        const poly = 'M' + xl.toFixed(1) + ' ' + yt.toFixed(1) +
+               'h' + ws +
+               'v' + h.toFixed(1) +
+               'h-' + ws +
+               'z';
+        path.push(poly);
+    }
+    paths.push(path.join('') || 'M0 0');
+
+    path.length = 0;
+    for ( const elem of blueNodes ) {
+        if ( elem === inspectorFrame ) { continue; }
+        if ( typeof elem.getBoundingClientRect !== 'function' ) { continue; }
+        const rect = elem.getBoundingClientRect();
+        const xl = rect.left;
+        const w = rect.width;
+        const yt = rect.top;
+        const h = rect.height;
+        const ws = w.toFixed(1);
+        const poly = 'M' + xl.toFixed(1) + ' ' + yt.toFixed(1) +
+               'h' + ws +
+               'v' + h.toFixed(1) +
+               'h-' + ws +
+               'z';
+        path.push(poly);
+    }
+    paths.push(path.join('') || 'M0 0');
+
+    contentInspectorChannel.toFrame({
+        what: 'svgPaths',
+        paths,
+    });
+};
+
+/******************************************************************************/
+
+const onScrolled = (( ) => {
+    let timer;
+    return ( ) => {
+        if ( timer ) { return; }
+        timer = window.requestAnimationFrame(( ) => {
+            timer = undefined;
+            highlightElements();
+        });
+    };
+})();
+
+const onMouseOver = ( ) => {
+    if ( blueNodes.length === 0 ) { return; }
+    blueNodes = [];
+    highlightElements();
+};
+
+/******************************************************************************/
+
+const selectNodes = (selector, nid) => {
+    const nodes = elementsFromSelector(selector);
+    if ( nid === '' ) { return nodes; }
+    for ( const node of nodes ) {
+        if ( nodeToIdMap.get(node) === nid ) {
+            return [ node ];
+        }
+    }
+    return [];
+};
+
+/******************************************************************************/
+
+const nodesFromFilter = selector => {
+    const out = [];
+    for ( const entry of roRedNodes ) {
+        if ( entry[1] === selector ) {
+            out.push(entry[0]);
+        }
+    }
+    return out;
+};
+
+/******************************************************************************/
+
+const toggleExceptions = (nodes, targetState) => {
+    for ( const node of nodes ) {
+        if ( targetState ) {
+            rwGreenNodes.add(node);
+        } else {
+            rwGreenNodes.delete(node);
+        }
+    }
+};
+
+const toggleFilter = (nodes, targetState) => {
+    for ( const node of nodes ) {
+        if ( targetState ) {
+            rwRedNodes.delete(node);
+        } else {
+            rwRedNodes.add(node);
+        }
+    }
+};
+
+const resetToggledNodes = ( ) => {
+    rwGreenNodes.clear();
+    rwRedNodes.clear();
+};
+
+/******************************************************************************/
+
+const startInspector = ( ) => {
+    const onReady = ( ) => {
+        window.addEventListener('scroll', onScrolled, {
+            capture: true,
+            passive: true,
+        });
+        window.addEventListener('mouseover', onMouseOver, {
+            capture: true,
+            passive: true,
+        });
+        contentInspectorChannel.toLogger(domLayout.get());
+        vAPI.domFilterer.toggle(false, highlightElements);
+    };
+    if ( document.readyState === 'loading' ) {
+        document.addEventListener('DOMContentLoaded', onReady, { once: true });
+    } else {
+        onReady();
+    }
+};
+
+/******************************************************************************/
+
+const shutdownInspector = ( ) => {
+    cosmeticFilterMapper.shutdown();
+    domLayout.shutdown();
+    window.removeEventListener('scroll', onScrolled, {
+        capture: true,
+        passive: true,
+    });
+    window.removeEventListener('mouseover', onMouseOver, {
+        capture: true,
+        passive: true,
+    });
+    contentInspectorChannel.shutdown();
+    if ( inspectorFrame ) {
+        inspectorFrame.remove();
+        inspectorFrame = null;
+    }
+    vAPI.userStylesheet.remove(inspectorCSS);
+    vAPI.userStylesheet.apply();
+    vAPI.inspectorFrame = false;
+};
+
+/******************************************************************************/
+/******************************************************************************/
+
+const onMessage = request => {
+    switch ( request.what ) {
+    case 'startInspector':
+        startInspector();
+        break;
+
+    case 'quitInspector':
+        shutdownInspector();
+        break;
+
+    case 'commitFilters':
+        highlightElements();
+        break;
+
+    case 'domLayout':
+        domLayout.get();
+        highlightElements();
+        break;
+
+    case 'highlightMode':
+        break;
+
+    case 'highlightOne':
+        blueNodes = selectNodes(request.selector, request.nid);
+        if ( blueNodes.length !== 0 ) {
+            blueNodes[0].scrollIntoView({
+                behavior: 'smooth',
+                block: 'nearest',
+                inline: 'nearest',
+            });
+        }
+        highlightElements();
+        break;
+
+    case 'resetToggledNodes':
+        resetToggledNodes();
+        highlightElements();
+        break;
+
+    case 'showCommitted':
+        blueNodes = [];
+        // TODO: show only the new filters and exceptions.
+        highlightElements();
+        break;
+
+    case 'showInteractive':
+        blueNodes = [];
+        highlightElements();
+        break;
+
+    case 'toggleFilter': {
+        const nodes = selectNodes(request.selector, request.nid);
+        if ( nodes.length !== 0 ) {
+            nodes[0].scrollIntoView({
+                behavior: 'smooth',
+                block: 'nearest',
+                inline: 'nearest',
+            });
+        }
+        toggleExceptions(nodesFromFilter(request.filter), request.target);
+        highlightElements();
+        break;
+    }
+    case 'toggleNodes': {
+        const nodes = selectNodes(request.selector, request.nid);
+        if ( nodes.length !== 0 ) {
+            nodes[0].scrollIntoView({
+                behavior: 'smooth',
+                block: 'nearest',
+                inline: 'nearest',
+            });
+        }
+        toggleFilter(nodes, request.target);
+        highlightElements();
+        break;
+    }
+    default:
+        break;
+    }
+};
+
+/*******************************************************************************
+ * 
+ * Establish two-way communication with logger/inspector window and
+ * inspector frame
+ * 
+ * */
+
+const contentInspectorChannel = (( ) => {
+    let toLoggerPort;
+    let toFramePort;
+
+    const toLogger = msg => {
+        if ( toLoggerPort === undefined ) { return; }
+        try {
+            toLoggerPort.postMessage(msg);
+        } catch(_) {
+            shutdownInspector();
+        }
+    };
+
+    const onLoggerMessage = msg => {
+        onMessage(msg);
+    };
+
+    const onLoggerDisconnect = ( ) => {
+        shutdownInspector();
+    };
+
+    const onLoggerConnect = port => {
+        browser.runtime.onConnect.removeListener(onLoggerConnect);
+        toLoggerPort = port;
+        port.onMessage.addListener(onLoggerMessage);
+        port.onDisconnect.addListener(onLoggerDisconnect);
+    };
+
+    const toFrame = msg => {
+        if ( toFramePort === undefined ) { return; }
+        toFramePort.postMessage(msg);
+    };
+
+    const shutdown = ( ) => {
+        if ( toFramePort !== undefined ) {
+            toFrame({ what: 'quitInspector' });
+            toFramePort.onmessage = null;
+            toFramePort.close();
+            toFramePort = undefined;
+        }
+        if ( toLoggerPort !== undefined ) {
+            toLoggerPort.onMessage.removeListener(onLoggerMessage);
+            toLoggerPort.onDisconnect.removeListener(onLoggerDisconnect);
+            toLoggerPort.disconnect();
+            toLoggerPort = undefined;
+        }
+        browser.runtime.onConnect.removeListener(onLoggerConnect);
+    };
+
+    const start = async ( ) => {
+        browser.runtime.onConnect.addListener(onLoggerConnect);
+        const inspectorArgs = await vAPI.messaging.send('domInspectorContent', {
+            what: 'getInspectorArgs',
+        });
+        if ( typeof inspectorArgs !== 'object' ) { return; }
+        if ( inspectorArgs === null ) { return; }
+        return new Promise(resolve => {
+            const iframe = document.createElement('iframe');
+            iframe.setAttribute(inspectorUniqueId, '');
+            document.documentElement.append(iframe);
+            iframe.addEventListener('load', ( ) => {
+                iframe.setAttribute(`${inspectorUniqueId}-loaded`, '');
+                const channel = new MessageChannel();
+                toFramePort = channel.port1;
+                toFramePort.onmessage = ev => {
+                    const msg = ev.data || {};
+                    if ( msg.what !== 'startInspector' ) { return; }
+                };
+                iframe.contentWindow.postMessage(
+                    { what: 'startInspector' },
+                    inspectorArgs.inspectorURL,
+                    [ channel.port2 ]
+                );
+                resolve(iframe);
+            }, { once: true });
+            iframe.contentWindow.location = inspectorArgs.inspectorURL;
+        });
+    };
+
+    return { start, toLogger, toFrame, shutdown };
+})();
+
+
+// Install DOM inspector widget
+const inspectorCSSStyle = [
+    'background: transparent',
+    'border: 0',
+    'border-radius: 0',
+    'box-shadow: none',
+    'color-scheme: light dark',
+    'display: block',
+    'filter: none',
+    'height: 100%',
+    'left: 0',
+    'margin: 0',
+    'max-height: none',
+    'max-width: none',
+    'min-height: unset',
+    'min-width: unset',
+    'opacity: 1',
+    'outline: 0',
+    'padding: 0',
+    'pointer-events: none',
+    'position: fixed',
+    'top: 0',
+    'transform: none',
+    'visibility: hidden',
+    'width: 100%',
+    'z-index: 2147483647',
+    ''
+].join(' !important;\n');
+
+const inspectorCSS = `
+:root > [${inspectorUniqueId}] {
+    ${inspectorCSSStyle}
+}
+:root > [${inspectorUniqueId}-loaded] {
+    visibility: visible !important;
+}
+`;
+
+vAPI.userStylesheet.add(inspectorCSS);
+vAPI.userStylesheet.apply();
+
+let inspectorFrame = await contentInspectorChannel.start();
+if ( inspectorFrame instanceof HTMLIFrameElement === false ) {
+    return shutdownInspector();
+}
+
+startInspector();
+
+/******************************************************************************/
+
+})();
+
+
+
+
+
+
+
+
+/*******************************************************************************
+
+    DO NOT:
+    - Remove the following code
+    - Add code beyond the following code
+    Reason:
+    - https://github.com/gorhill/uBlock/pull/3721
+    - uBO never uses the return value from injected content scripts
+
+**/
+
+void 0;
diff --git a/src/js/scriptlets/dom-survey-elements.js b/src/js/scriptlets/dom-survey-elements.js
new file mode 100644
index 0000000..1582596
--- /dev/null
+++ b/src/js/scriptlets/dom-survey-elements.js
@@ -0,0 +1,72 @@
+/*******************************************************************************
+
+    uBlock Origin - a comprehensive, efficient content blocker
+    Copyright (C) 2015-present Raymond Hill
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see {http://www.gnu.org/licenses/}.
+
+    Home: https://github.com/gorhill/uBlock
+*/
+
+'use strict';
+
+/******************************************************************************/
+
+// https://github.com/uBlockOrigin/uBlock-issues/issues/756
+//   Keep in mind CPU usage with large DOM and/or filterset.
+
+(( ) => {
+    if ( typeof vAPI !== 'object' ) { return; }
+
+    const t0 = Date.now();
+
+    if ( vAPI.domSurveyElements instanceof Object === false ) {
+        vAPI.domSurveyElements = {
+            busy: false,
+            hiddenElementCount: Number.NaN,
+            surveyTime: t0,
+        };
+    }
+    const surveyResults = vAPI.domSurveyElements;
+
+    if ( surveyResults.busy ) { return; }
+    surveyResults.busy = true;
+
+    if ( surveyResults.surveyTime < vAPI.domMutationTime ) {
+        surveyResults.hiddenElementCount = Number.NaN;
+    }
+    surveyResults.surveyTime = t0;
+
+    if ( isNaN(surveyResults.hiddenElementCount) ) {
+        surveyResults.hiddenElementCount = (( ) => {
+            if ( vAPI.domFilterer instanceof Object === false ) { return 0; }
+            const details = vAPI.domFilterer.getAllSelectors(0b11);
+            if (
+                Array.isArray(details.declarative) === false ||
+                details.declarative.length === 0
+            ) {
+                return 0;
+            }
+            return document.querySelectorAll(
+                details.declarative.join(',\n')
+            ).length;
+        })();
+    }
+
+    surveyResults.busy = false;
+
+    // IMPORTANT: This is returned to the injector, so this MUST be
+    //            the last statement.
+    return surveyResults.hiddenElementCount;
+})();
diff --git a/src/js/scriptlets/dom-survey-scripts.js b/src/js/scriptlets/dom-survey-scripts.js
new file mode 100644
index 0000000..e5300ff
--- /dev/null
+++ b/src/js/scriptlets/dom-survey-scripts.js
@@ -0,0 +1,126 @@
+/*******************************************************************************
+
+    uBlock Origin - a comprehensive, efficient content blocker
+    Copyright (C) 2015-present Raymond Hill
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see {http://www.gnu.org/licenses/}.
+
+    Home: https://github.com/gorhill/uBlock
+*/
+
+'use strict';
+
+/******************************************************************************/
+
+// Scriptlets to count the number of script tags in a document.
+
+(( ) => {
+    if ( typeof vAPI !== 'object' ) { return; }
+
+    const t0 = Date.now();
+
+    if ( vAPI.domSurveyScripts instanceof Object === false ) {
+        vAPI.domSurveyScripts = {
+            busy: false,
+            scriptCount: -1,
+            surveyTime: t0,
+        };
+    }
+    const surveyResults = vAPI.domSurveyScripts;
+
+    if ( surveyResults.busy ) { return; }
+    surveyResults.busy = true;
+
+    if ( surveyResults.surveyTime < vAPI.domMutationTime ) {
+        surveyResults.scriptCount = -1;
+    }
+    surveyResults.surveyTime = t0;
+
+    if ( surveyResults.scriptCount === -1 ) {
+        const reInlineScript = /^(data:|blob:|$)/;
+        let inlineScriptCount = 0;
+        let scriptCount = 0;
+        for ( const script of document.scripts ) {
+            if ( reInlineScript.test(script.src) ) {
+                inlineScriptCount = 1;
+                continue;
+            }
+            scriptCount += 1;
+            if ( scriptCount === 99 ) { break; }
+        }
+        scriptCount += inlineScriptCount;
+        if ( scriptCount !== 0 ) {
+            surveyResults.scriptCount = scriptCount;
+        }
+    }
+
+    // https://github.com/uBlockOrigin/uBlock-issues/issues/756
+    //   Keep trying to find inline script-like instances but only if we
+    //   have the time-budget to do so.
+    if ( surveyResults.scriptCount === -1 ) {
+        if ( document.querySelector('a[href^="javascript:"]') !== null ) {
+            surveyResults.scriptCount = 1;
+        }
+    }
+
+    // https://github.com/uBlockOrigin/uBlock-issues/issues/1756
+    //   Mind that there might be no body element.
+    if ( surveyResults.scriptCount === -1 && document.body !== null ) {
+        surveyResults.scriptCount = 0;
+        const onHandlers = new Set([
+            'onabort', 'onblur', 'oncancel', 'oncanplay',
+            'oncanplaythrough', 'onchange', 'onclick', 'onclose',
+            'oncontextmenu', 'oncuechange', 'ondblclick', 'ondrag',
+            'ondragend', 'ondragenter', 'ondragexit', 'ondragleave',
+            'ondragover', 'ondragstart', 'ondrop', 'ondurationchange',
+            'onemptied', 'onended', 'onerror', 'onfocus',
+            'oninput', 'oninvalid', 'onkeydown', 'onkeypress',
+            'onkeyup', 'onload', 'onloadeddata', 'onloadedmetadata',
+            'onloadstart', 'onmousedown', 'onmouseenter', 'onmouseleave',
+            'onmousemove', 'onmouseout', 'onmouseover', 'onmouseup',
+            'onwheel', 'onpause', 'onplay', 'onplaying',
+            'onprogress', 'onratechange', 'onreset', 'onresize',
+            'onscroll', 'onseeked', 'onseeking', 'onselect',
+            'onshow', 'onstalled', 'onsubmit', 'onsuspend',
+            'ontimeupdate', 'ontoggle', 'onvolumechange', 'onwaiting',
+            'onafterprint', 'onbeforeprint', 'onbeforeunload', 'onhashchange',
+            'onlanguagechange', 'onmessage', 'onoffline', 'ononline',
+            'onpagehide', 'onpageshow', 'onrejectionhandled', 'onpopstate',
+            'onstorage', 'onunhandledrejection', 'onunload',
+            'oncopy', 'oncut', 'onpaste'
+        ]);
+        const nodeIter = document.createNodeIterator(
+            document.body,
+            NodeFilter.SHOW_ELEMENT
+        );
+        for (;;) {
+            const node = nodeIter.nextNode();
+            if ( node === null ) { break; }
+            if ( node.hasAttributes() === false ) { continue; }
+            for ( const attr of node.getAttributeNames() ) {
+                if ( onHandlers.has(attr) === false ) { continue; }
+                surveyResults.scriptCount = 1;
+                break;
+            }
+        }
+    }
+
+    surveyResults.busy = false;
+
+    // IMPORTANT: This is returned to the injector, so this MUST be
+    //            the last statement.
+    if ( surveyResults.scriptCount !== -1 ) {
+        return surveyResults.scriptCount;
+    }
+})();
diff --git a/src/js/scriptlets/epicker.js b/src/js/scriptlets/epicker.js
new file mode 100644
index 0000000..80489e8
--- /dev/null
+++ b/src/js/scriptlets/epicker.js
@@ -0,0 +1,1356 @@
+/*******************************************************************************
+
+    uBlock Origin - a comprehensive, efficient content blocker
+    Copyright (C) 2014-present Raymond Hill
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see {http://www.gnu.org/licenses/}.
+
+    Home: https://github.com/gorhill/uBlock
+*/
+
+/* global CSS */
+
+'use strict';
+
+/******************************************************************************/
+/******************************************************************************/
+
+(async ( ) => {
+
+/******************************************************************************/
+
+if ( typeof vAPI !== 'object' ) { return; }
+if ( typeof vAPI === null ) { return; }
+
+if ( vAPI.pickerFrame ) { return; }
+vAPI.pickerFrame = true;
+
+const pickerUniqueId = vAPI.randomToken();
+
+const reCosmeticAnchor = /^#(\$|\?|\$\?)?#/;
+
+const netFilterCandidates = [];
+const cosmeticFilterCandidates = [];
+
+let targetElements = [];
+let candidateElements = [];
+let bestCandidateFilter = null;
+
+const lastNetFilterSession = window.location.host + window.location.pathname;
+let lastNetFilterHostname = '';
+let lastNetFilterUnion = '';
+
+const hideBackgroundStyle = 'background-image:none!important;';
+
+/******************************************************************************/
+
+const safeQuerySelectorAll = function(node, selector) {
+    if ( node !== null ) {
+        try {
+            return node.querySelectorAll(selector);
+        } catch (e) {
+        }
+    }
+    return [];
+};
+
+/******************************************************************************/
+
+const getElementBoundingClientRect = function(elem) {
+    let rect = typeof elem.getBoundingClientRect === 'function'
+        ? elem.getBoundingClientRect()
+        : { height: 0, left: 0, top: 0, width: 0 };
+
+    // https://github.com/gorhill/uBlock/issues/1024
+    // Try not returning an empty bounding rect.
+    if ( rect.width !== 0 && rect.height !== 0 ) {
+        return rect;
+    }
+    if ( elem.shadowRoot instanceof DocumentFragment ) {
+        return getElementBoundingClientRect(elem.shadowRoot);
+    }
+
+    let left = rect.left,
+        right = left + rect.width,
+        top = rect.top,
+        bottom = top + rect.height;
+
+    for ( const child of elem.children ) {
+        rect = getElementBoundingClientRect(child);
+        if ( rect.width === 0 || rect.height === 0 ) { continue; }
+        if ( rect.left < left ) { left = rect.left; }
+        if ( rect.right > right ) { right = rect.right; }
+        if ( rect.top < top ) { top = rect.top; }
+        if ( rect.bottom > bottom ) { bottom = rect.bottom; }
+    }
+
+    return {
+        bottom,
+        height: bottom - top,
+        left,
+        right,
+        top,
+        width: right - left
+    };
+};
+
+/******************************************************************************/
+
+const highlightElements = function(elems, force) {
+    // To make mouse move handler more efficient
+    if (
+        (force !== true) &&
+        (elems.length === targetElements.length) &&
+        (elems.length === 0 || elems[0] === targetElements[0])
+    ) {
+        return;
+    }
+    targetElements = [];
+
+    const ow = self.innerWidth;
+    const oh = self.innerHeight;
+    const islands = [];
+
+    for ( const elem of elems ) {
+        if ( elem === pickerFrame ) { continue; }
+        targetElements.push(elem);
+        const rect = getElementBoundingClientRect(elem);
+        // Ignore offscreen areas
+        if (
+            rect.left > ow || rect.top > oh ||
+            rect.left + rect.width < 0 || rect.top + rect.height < 0
+        ) {
+            continue;
+        }
+        islands.push(
+            `M${rect.left} ${rect.top}h${rect.width}v${rect.height}h-${rect.width}z`
+        );
+    }
+
+    pickerFramePort.postMessage({
+        what: 'svgPaths',
+        ocean: `M0 0h${ow}v${oh}h-${ow}z`,
+        islands: islands.join(''),
+    });
+};
+
+/******************************************************************************/
+
+const mergeStrings = function(urls) {
+    if ( urls.length === 0 ) { return ''; }
+    if (
+        urls.length === 1 ||
+        self.diff_match_patch instanceof Function === false
+    ) {
+        return urls[0];
+    }
+    const differ = new self.diff_match_patch();
+    let merged = urls[0];
+    for ( let i = 1; i < urls.length; i++ ) {
+        // The differ works at line granularity: we insert a linefeed after
+        // each character to trick the differ to work at character granularity.
+        const diffs = differ.diff_main(
+            urls[i].split('').join('\n'),
+            merged.split('').join('\n')
+        );
+        const result = [];
+        for ( const diff of diffs ) {
+            if ( diff[0] !== 0 ) {
+                result.push('*');
+            } else {
+                result.push(diff[1].replace(/\n+/g, ''));
+            }
+            merged = result.join('');
+        }
+    }
+    // Keep usage of wildcards to a sane level, too many of them can cause
+    // high overhead filters
+    merged = merged.replace(/^\*+$/, '')
+                   .replace(/\*{2,}/g, '*')
+                   .replace(/([^*]{1,3}\*)(?:[^*]{1,3}\*)+/g, '$1');
+
+    // https://github.com/uBlockOrigin/uBlock-issues/issues/1494
+    let pos = merged.indexOf('/');
+    if ( pos === -1 ) { pos = merged.length; }
+    return merged.slice(0, pos).includes('*') ? urls[0] : merged;
+};
+
+/******************************************************************************/
+
+// Remove fragment part from a URL.
+
+const trimFragmentFromURL = function(url) {
+    const pos = url.indexOf('#');
+    return pos !== -1 ? url.slice(0, pos) : url;
+};
+
+/******************************************************************************/
+
+// https://github.com/gorhill/uBlock/issues/1897
+// Ignore `data:` URI, they can't be handled by an HTTP observer.
+
+const backgroundImageURLFromElement = function(elem) {
+    const style = window.getComputedStyle(elem);
+    const bgImg = style.backgroundImage || '';
+    const matches = /^url\((["']?)([^"']+)\1\)$/.exec(bgImg);
+    const url = matches !== null && matches.length === 3 ? matches[2] : '';
+    return url.lastIndexOf('data:', 0) === -1
+        ? trimFragmentFromURL(url.slice(0, 1024))
+        : '';
+};
+
+/******************************************************************************/
+
+// https://github.com/gorhill/uBlock/issues/1725#issuecomment-226479197
+//   Limit returned string to 1024 characters.
+//   Also, return only URLs which will be seen by an HTTP observer.
+// https://github.com/uBlockOrigin/uBlock-issues/issues/2260
+//   Maybe get to the actual URL indirectly.
+const resourceURLsFromElement = function(elem) {
+    const urls = [];
+    const tagName = elem.localName;
+    const prop = netFilter1stSources[tagName];
+    if ( prop === undefined ) {
+        const url = backgroundImageURLFromElement(elem);
+        if ( url !== '' ) { urls.push(url); }
+        return urls;
+    }
+    let s = elem[prop];
+    if ( s instanceof SVGAnimatedString ) {
+        s = s.baseVal;
+    }
+    if ( typeof s === 'string' && /^https?:\/\//.test(s) ) {
+        urls.push(trimFragmentFromURL(s.slice(0, 1024)));
+    }
+    resourceURLsFromSrcset(elem, urls);
+    resourceURLsFromPicture(elem, urls);
+    return urls;
+};
+
+// https://html.spec.whatwg.org/multipage/images.html#parsing-a-srcset-attribute
+// https://github.com/uBlockOrigin/uBlock-issues/issues/1071
+const resourceURLsFromSrcset = function(elem, out) {
+    let srcset = elem.srcset;
+    if ( typeof srcset !== 'string' || srcset === '' ) { return; }
+    for(;;) {
+        // trim whitespace
+        srcset = srcset.trim();
+        if ( srcset.length === 0 ) { break; }
+        // abort in case of leading comma
+        if ( /^,/.test(srcset) ) { break; }
+        // collect and consume all non-whitespace characters
+        let match = /^\S+/.exec(srcset);
+        if ( match === null ) { break; }
+        srcset = srcset.slice(match.index + match[0].length);
+        let url = match[0];
+        // consume descriptor, if any
+        if ( /,$/.test(url) ) {
+            url = url.replace(/,$/, '');
+            if ( /,$/.test(url) ) { break; }
+        } else {
+            match = /^[^,]*(?:\(.+?\))?[^,]*(?:,|$)/.exec(srcset);
+            if ( match === null ) { break; }
+            srcset = srcset.slice(match.index + match[0].length);
+        }
+        const parsedURL = new URL(url, document.baseURI);
+        if ( parsedURL.pathname.length === 0 ) { continue; }
+        out.push(trimFragmentFromURL(parsedURL.href));
+    }
+};
+
+// https://github.com/uBlockOrigin/uBlock-issues/issues/2069#issuecomment-1080600661
+// https://developer.mozilla.org/en-US/docs/Web/HTML/Element/picture
+const resourceURLsFromPicture = function(elem, out) {
+    if ( elem.localName === 'source' ) { return; }
+    const picture = elem.parentElement;
+    if ( picture === null || picture.localName !== 'picture' ) { return; }
+    const sources = picture.querySelectorAll(':scope > source');
+    for ( const source of sources ) {
+        const urls = resourceURLsFromElement(source);
+        if ( urls.length === 0 ) { continue; }
+        out.push(...urls);
+    }
+};
+
+/******************************************************************************/
+
+const netFilterFromUnion = function(patternIn, out) {
+    // Reset reference filter when dealing with unrelated URLs
+    const currentHostname = self.location.hostname;
+    if (
+        lastNetFilterUnion === '' ||
+        currentHostname === '' ||
+        currentHostname !== lastNetFilterHostname
+    ) {
+        lastNetFilterHostname = currentHostname;
+        lastNetFilterUnion = patternIn;
+        vAPI.messaging.send('elementPicker', {
+            what: 'elementPickerEprom',
+            lastNetFilterSession,
+            lastNetFilterHostname,
+            lastNetFilterUnion,
+        });
+        return;
+    }
+
+    // Related URLs
+    lastNetFilterHostname = currentHostname;
+    let patternOut = mergeStrings([ patternIn, lastNetFilterUnion ]);
+    if ( patternOut !== '/*' && patternOut !== patternIn ) {
+        const filter = `||${patternOut}`;
+        if ( out.indexOf(filter) === -1 ) {
+            out.push(filter);
+        }
+        lastNetFilterUnion = patternOut;
+    }
+
+    // Remember across element picker sessions
+    vAPI.messaging.send('elementPicker', {
+        what: 'elementPickerEprom',
+        lastNetFilterSession,
+        lastNetFilterHostname,
+        lastNetFilterUnion,
+    });
+};
+
+/******************************************************************************/
+
+// Extract the best possible net filter, i.e. as specific as possible.
+
+const netFilterFromElement = function(elem) {
+    if ( elem === null ) { return 0; }
+    if ( elem.nodeType !== 1 ) { return 0; }
+    const urls = resourceURLsFromElement(elem);
+    if ( urls.length === 0 ) { return 0; }
+
+    if ( candidateElements.indexOf(elem) === -1 ) {
+        candidateElements.push(elem);
+    }
+
+    const candidates = netFilterCandidates;
+    const len = candidates.length;
+
+    for ( let i = 0; i < urls.length; i++ ) {
+        urls[i] = urls[i].replace(/^https?:\/\//, '');
+    }
+    const pattern = mergeStrings(urls);
+
+
+    if ( bestCandidateFilter === null && elem.matches('html,body') === false ) {
+        bestCandidateFilter = {
+            type: 'net',
+            filters: candidates,
+            slot: candidates.length
+        };
+    }
+
+    candidates.push(`||${pattern}`);
+
+    // Suggest a less narrow filter if possible
+    const pos = pattern.indexOf('?');
+    if ( pos !== -1 ) {
+        candidates.push(`||${pattern.slice(0, pos)}`);
+    }
+
+    // Suggest a filter which is a result of combining more than one URL.
+    netFilterFromUnion(pattern, candidates);
+
+    return candidates.length - len;
+};
+
+const netFilter1stSources = {
+     'audio': 'src',
+     'embed': 'src',
+    'iframe': 'src',
+       'img': 'src',
+     'image': 'href',
+    'object': 'data',
+    'source': 'src',
+     'video': 'src'
+};
+
+const filterTypes = {
+     'audio': 'media',
+     'embed': 'object',
+    'iframe': 'subdocument',
+       'img': 'image',
+    'object': 'object',
+     'video': 'media',
+};
+
+/******************************************************************************/
+
+// Extract the best possible cosmetic filter, i.e. as specific as possible.
+
+// https://github.com/gorhill/uBlock/issues/1725
+//   Also take into account the `src` attribute for `img` elements -- and limit
+//   the value to the 1024 first characters.
+
+const cosmeticFilterFromElement = function(elem) {
+    if ( elem === null ) { return 0; }
+    if ( elem.nodeType !== 1 ) { return 0; }
+    if ( noCosmeticFiltering ) { return 0; }
+
+    if ( candidateElements.indexOf(elem) === -1 ) {
+        candidateElements.push(elem);
+    }
+
+    let selector = '';
+
+    // Id
+    let v = typeof elem.id === 'string' && CSS.escape(elem.id);
+    if ( v ) {
+        selector = '#' + v;
+    }
+
+    // Class(es)
+    v = elem.classList;
+    if ( v ) {
+        let i = v.length || 0;
+        while ( i-- ) {
+            selector += '.' + CSS.escape(v.item(i));
+        }
+    }
+
+    // Tag name
+    const tagName = CSS.escape(elem.localName);
+
+    // Use attributes if still no selector found.
+    // https://github.com/gorhill/uBlock/issues/1901
+    //   Trim attribute value, this may help in case of malformed HTML.
+    //
+    // https://github.com/uBlockOrigin/uBlock-issues/issues/1923
+    //   Escape unescaped `"` in attribute values
+    if ( selector === '' ) {
+        let attributes = [], attr;
+        switch ( tagName ) {
+        case 'a':
+            v = elem.getAttribute('href');
+            if ( v ) {
+                v = v.trim().replace(/\?.*$/, '');
+                if ( v.length ) {
+                    attributes.push({ k: 'href', v: v });
+                }
+            }
+            break;
+        case 'iframe':
+        case 'img':
+            v = elem.getAttribute('src');
+            if ( v && v.length !== 0 ) {
+                v = v.trim();
+                if ( v.startsWith('data:') ) {
+                    let pos = v.indexOf(',');
+                    if ( pos !== -1 ) {
+                        v = v.slice(0, pos + 1);
+                    }
+                } else if ( v.startsWith('blob:') ) {
+                    v = new URL(v.slice(5));
+                    v.pathname = '';
+                    v = 'blob:' + v.href;
+                }
+                attributes.push({ k: 'src', v: v.slice(0, 256) });
+                break;
+            }
+            v = elem.getAttribute('alt');
+            if ( v && v.length !== 0 ) {
+                attributes.push({ k: 'alt', v: v });
+                break;
+            }
+            break;
+        default:
+            break;
+        }
+        while ( (attr = attributes.pop()) ) {
+            if ( attr.v.length === 0 ) { continue; }
+            const w = attr.v.replace(/([^\\])"/g, '$1\\"');
+            v = elem.getAttribute(attr.k);
+            if ( attr.v === v ) {
+                selector += `[${attr.k}="${w}"]`;
+            } else if ( v.startsWith(attr.v) ) {
+                selector += `[${attr.k}^="${w}"]`;
+            } else {
+                selector += `[${attr.k}*="${w}"]`;
+            }
+        }
+    }
+
+    // https://github.com/uBlockOrigin/uBlock-issues/issues/17
+    //   If selector is ambiguous at this point, add the element name to
+    //   further narrow it down.
+    const parentNode = elem.parentNode;
+    if (
+        selector === '' ||
+        safeQuerySelectorAll(parentNode, `:scope > ${selector}`).length > 1
+    ) {
+        selector = tagName + selector;
+    }
+
+    // https://github.com/chrisaljoudi/uBlock/issues/637
+    //   If the selector is still ambiguous at this point, further narrow using
+    //   `nth-of-type`. It is preferable to use `nth-of-type` as opposed to
+    //   `nth-child`, as `nth-of-type` is less volatile.
+    if ( safeQuerySelectorAll(parentNode, `:scope > ${selector}`).length > 1 ) {
+        let i = 1;
+        while ( elem.previousSibling !== null ) {
+            elem = elem.previousSibling;
+            if (
+                typeof elem.localName === 'string' &&
+                elem.localName === tagName
+            ) {
+                i++;
+            }
+        }
+        selector += `:nth-of-type(${i})`;
+    }
+
+    if ( bestCandidateFilter === null ) {
+        bestCandidateFilter = {
+            type: 'cosmetic',
+            filters: cosmeticFilterCandidates,
+            slot: cosmeticFilterCandidates.length
+        };
+    }
+
+    cosmeticFilterCandidates.push(`##${selector}`);
+
+    return 1;
+};
+
+/******************************************************************************/
+
+const filtersFrom = function(x, y) {
+    bestCandidateFilter = null;
+    netFilterCandidates.length = 0;
+    cosmeticFilterCandidates.length = 0;
+    candidateElements.length = 0;
+
+    // We need at least one element.
+    let first = null;
+    if ( typeof x === 'number' ) {
+        first = elementFromPoint(x, y);
+    } else if ( x instanceof HTMLElement ) {
+        first = x;
+        x = undefined;
+    }
+
+    // https://github.com/gorhill/uBlock/issues/1545
+    //   Network filter candidates from all other elements found at [x,y].
+    // https://www.reddit.com/r/uBlockOrigin/comments/qmjk36/
+    //   Extract network candidates first.
+    if ( typeof x === 'number' ) {
+        const magicAttr = `${pickerUniqueId}-clickblind`;
+        pickerFrame.setAttribute(magicAttr, '');
+        const elems = document.elementsFromPoint(x, y);
+        pickerFrame.removeAttribute(magicAttr);
+        for ( const elem of elems ) {
+            netFilterFromElement(elem);
+        }
+    } else if ( first !== null ) {
+        netFilterFromElement(first);
+    }
+
+    // Cosmetic filter candidates from ancestors.
+    // https://github.com/gorhill/uBlock/issues/2519
+    // https://github.com/uBlockOrigin/uBlock-issues/issues/17
+    //   Prepend `body` if full selector is ambiguous.
+    let elem = first;
+    while ( elem && elem !== document.body ) {
+        cosmeticFilterFromElement(elem);
+        elem = elem.parentNode;
+    }
+    // The body tag is needed as anchor only when the immediate child
+    // uses `nth-of-type`.
+    let i = cosmeticFilterCandidates.length;
+    if ( i !== 0 ) {
+        const selector = cosmeticFilterCandidates[i-1].slice(2);
+        if ( safeQuerySelectorAll(document.body, selector).length > 1 ) {
+            cosmeticFilterCandidates.push('##body');
+        }
+    }
+
+    // https://github.com/gorhill/uBlock/commit/ebaa8a8bb28aef043a68c99965fe6c128a3fe5e4#commitcomment-63818019
+    //   If still no best candidate, just use whatever is available in network
+    //   filter candidates -- which may have been previously skipped in favor
+    //   of cosmetic filters.
+    if ( bestCandidateFilter === null && netFilterCandidates.length !== 0 ) {
+        bestCandidateFilter = {
+            type: 'net',
+            filters: netFilterCandidates,
+            slot: 0
+        };
+    }
+
+    return netFilterCandidates.length + cosmeticFilterCandidates.length;
+};
+
+/*******************************************************************************
+
+    filterToDOMInterface.queryAll
+    @desc   Look-up all the HTML elements matching the filter passed in
+            argument.
+    @param  string, a cosmetic or network filter.
+    @param  function, called once all items matching the filter have been
+            collected.
+    @return array, or undefined if the filter is invalid.
+
+    filterToDOMInterface.preview
+    @desc   Apply/unapply filter to the DOM.
+    @param  string, a cosmetic of network filter, or literal false to remove
+            the effects of the filter on the DOM.
+    @return undefined.
+
+    TODO: need to be revised once I implement chained cosmetic operators.
+
+*/
+
+const filterToDOMInterface = (( ) => {
+    const reHnAnchorPrefix = '^[\\w-]+://(?:[^/?#]+\\.)?';
+    const reCaret = '(?:[^%.0-9a-z_-]|$)';
+    const rePseudoElements = /:(?::?after|:?before|:[a-z-]+)$/;
+
+    // Net filters: we need to lookup manually -- translating into a foolproof
+    // CSS selector is just not possible.
+    //
+    // https://github.com/chrisaljoudi/uBlock/issues/945
+    //   Transform into a regular expression, this allows the user to
+    //   edit and insert wildcard(s) into the proposed filter.
+    // https://www.reddit.com/r/uBlockOrigin/comments/c5do7w/
+    //   Better handling of pure hostname filters. Also, discard single
+    //   alphanumeric character filters.
+    const fromNetworkFilter = function(filter) {
+        const out = [];
+        if ( /^[0-9a-z]$/i.test(filter) ) { return out; }
+        let reStr = '';
+        if (
+            filter.length > 2 &&
+            filter.startsWith('/') &&
+            filter.endsWith('/')
+        ) {
+            reStr = filter.slice(1, -1);
+        } else if ( /^\w[\w.-]*[a-z]$/i.test(filter) ) {
+            reStr = reHnAnchorPrefix +
+                    filter.toLowerCase().replace(/\./g, '\\.') +
+                    reCaret;
+        } else {
+            let rePrefix = '', reSuffix = '';
+            if ( filter.startsWith('||') ) {
+                rePrefix = reHnAnchorPrefix;
+                filter = filter.slice(2);
+            } else if ( filter.startsWith('|') ) {
+                rePrefix = '^';
+                filter = filter.slice(1);   
+            }
+            if ( filter.endsWith('|') ) {
+                reSuffix = '$';
+                filter = filter.slice(0, -1);
+            }
+            reStr = rePrefix +
+                    filter.replace(/[.+?${}()|[\]\\]/g, '\\$&')
+                          .replace(/\*+/g, '.*')
+                          .replace(/\^/g, reCaret) +
+                    reSuffix;
+        }
+        let reFilter = null;
+        try {
+            reFilter = new RegExp(reStr, 'i');
+        }
+        catch (e) {
+            return out;
+        }
+
+        // Lookup by tag names.
+        // https://github.com/uBlockOrigin/uBlock-issues/issues/2260
+        //   Maybe get to the actual URL indirectly.
+        const elems = document.querySelectorAll(
+            Object.keys(netFilter1stSources).join()
+        );
+        for ( const elem of elems ) {
+            const srcProp = netFilter1stSources[elem.localName];
+            let src = elem[srcProp];
+            if ( src instanceof SVGAnimatedString ) {
+                src = src.baseVal;
+            }
+            if (
+                typeof src === 'string' &&
+                    reFilter.test(src) ||
+                typeof elem.currentSrc === 'string' &&
+                    reFilter.test(elem.currentSrc)
+            ) {
+                out.push({
+                    elem,
+                    src: srcProp,
+                    opt: filterTypes[elem.localName],
+                    style: vAPI.hideStyle,
+                });
+            }
+        }
+
+        // Find matching background image in current set of candidate elements.
+        for ( const elem of candidateElements ) {
+            if ( reFilter.test(backgroundImageURLFromElement(elem)) ) {
+                out.push({
+                    elem,
+                    bg: true,
+                    opt: 'image',
+                    style: hideBackgroundStyle,
+                });
+            }
+        }
+
+        return out;
+    };
+
+    // Cosmetic filters: these are straight CSS selectors.
+    //
+    // https://github.com/uBlockOrigin/uBlock-issues/issues/389
+    //   Test filter using comma-separated list to better detect invalid CSS
+    //   selectors.
+    //
+    // https://github.com/gorhill/uBlock/issues/2515
+    //   Remove trailing pseudo-element when querying.
+    const fromPlainCosmeticFilter = function(raw) {
+        let elems;
+        try {
+            document.documentElement.matches(`${raw},\na`);
+            elems = document.querySelectorAll(
+                raw.replace(rePseudoElements, '')
+            );
+        }
+        catch (e) {
+            return;
+        }
+        const out = [];
+        for ( const elem of elems ) {
+            if ( elem === pickerFrame ) { continue; }
+            out.push({ elem, raw, style: vAPI.hideStyle });
+        }
+        return out;
+    };
+
+    // https://github.com/gorhill/uBlock/issues/1772
+    //   Handle procedural cosmetic filters.
+    //
+    // https://github.com/gorhill/uBlock/issues/2515
+    //   Remove trailing pseudo-element when querying.
+    const fromCompiledCosmeticFilter = function(raw) {
+        if ( noCosmeticFiltering ) { return; }
+        if ( typeof raw !== 'string' ) { return; }
+        let elems, style;
+        try {
+            const o = JSON.parse(raw);
+            elems = vAPI.domFilterer.createProceduralFilter(o).exec();
+            switch ( o.action && o.action[0] || '' ) {
+            case '':
+            case 'remove':
+                style = vAPI.hideStyle;
+                break;
+            case 'style':
+                style = o.action[1];
+                break;
+            default:
+                break;
+            }
+        } catch(ex) {
+            return;
+        }
+        if ( !elems ) { return; }
+        const out = [];
+        for ( const elem of elems ) {
+            out.push({ elem, raw, style });
+        }
+        return out;
+    };
+
+    vAPI.epickerStyleProxies = vAPI.epickerStyleProxies || new Map();
+
+    let lastFilter;
+    let lastResultset;
+    let previewing = false;
+
+    const queryAll = function(details) {
+        let { filter, compiled } = details;
+        filter = filter.trim();
+        if ( filter === lastFilter ) { return lastResultset; }
+        unapply();
+        if ( filter === '' || filter === '!' ) {
+            lastFilter = '';
+            lastResultset = undefined;
+            return;
+        }
+        lastFilter = filter;
+        if ( reCosmeticAnchor.test(filter) === false ) {
+            lastResultset = fromNetworkFilter(filter);
+            if ( previewing ) { apply(); }
+            return lastResultset;
+        }
+        lastResultset = fromPlainCosmeticFilter(compiled);
+        if ( lastResultset ) {
+            if ( previewing ) { apply(); }
+            return lastResultset;
+        }
+        // Procedural cosmetic filter
+        lastResultset = fromCompiledCosmeticFilter(compiled);
+        if ( previewing ) { apply(); }
+        return lastResultset;
+    };
+
+    const apply = function() {
+        unapply();
+        if ( Array.isArray(lastResultset) === false ) { return; }
+        const rootElem = document.documentElement;
+        for ( const { elem, style } of lastResultset ) {
+            if ( elem === pickerFrame ) { continue; }
+            if ( style === undefined ) { continue; }
+            if ( elem === rootElem && style === vAPI.hideStyle ) { continue; }
+            let styleToken = vAPI.epickerStyleProxies.get(style);
+            if ( styleToken === undefined ) {
+                styleToken = vAPI.randomToken();
+                vAPI.epickerStyleProxies.set(style, styleToken);
+                vAPI.userStylesheet.add(`[${styleToken}]\n{${style}}`, true);
+            }
+            elem.setAttribute(styleToken, '');
+        }
+    };
+
+    const unapply = function() {
+        for ( const styleToken of vAPI.epickerStyleProxies.values() ) {
+            for ( const elem of document.querySelectorAll(`[${styleToken}]`) ) {
+                elem.removeAttribute(styleToken);
+            }
+        }
+    };
+
+    // https://www.reddit.com/r/uBlockOrigin/comments/c62irc/
+    //   Support injecting the cosmetic filters into the DOM filterer
+    //   immediately rather than wait for the next page load.
+    const preview = function(state, permanent = false) {
+        previewing = state !== false;
+        if ( previewing === false ) {
+            return unapply();
+        }
+        if ( Array.isArray(lastResultset) === false ) { return; }
+        if ( permanent === false || reCosmeticAnchor.test(lastFilter) === false ) {
+            return apply();
+        }
+        if ( noCosmeticFiltering ) { return; }
+        const cssSelectors = new Set();
+        const proceduralSelectors = new Set();
+        for ( const { raw } of lastResultset ) {
+            if ( raw.startsWith('{') ) {
+                proceduralSelectors.add(raw);
+            } else {
+                cssSelectors.add(raw);
+            }
+        }
+        if ( cssSelectors.size !== 0 ) {
+            vAPI.domFilterer.addCSS(
+                `${Array.from(cssSelectors).join('\n')}\n{${vAPI.hideStyle}}`,
+                { mustInject: true }
+            );
+        }
+        if ( proceduralSelectors.size !== 0 ) {
+            vAPI.domFilterer.addProceduralSelectors(
+                Array.from(proceduralSelectors)
+            );
+        }
+    };
+
+    return { preview, queryAll };
+})();
+
+/******************************************************************************/
+
+const onOptimizeCandidates = function(details) {
+    const { candidates } = details;
+    const results = [];
+    for ( const paths of candidates ) {
+        let count = Number.MAX_SAFE_INTEGER;
+        let selector = '';
+        for ( let i = 0, n = paths.length; i < n; i++ ) {
+            const s = paths.slice(n - i - 1).join('');
+            const elems = document.querySelectorAll(s);
+            if ( elems.length < count ) {
+                selector = s;
+                count = elems.length;
+            }
+        }
+        results.push({ selector: `##${selector}`, count });
+    }
+    // Sort by most match count and shortest selector to least match count and
+    // longest selector.
+    results.sort((a, b) => {
+        const r = b.count - a.count;
+        if ( r !== 0 ) { return r; }
+        return a.selector.length - b.selector.length;
+    });
+    pickerFramePort.postMessage({
+        what: 'candidatesOptimized',
+        candidates: results.map(a => a.selector),
+        slot: details.slot,
+    });
+};
+
+/******************************************************************************/
+
+const showDialog = function(options) {
+    pickerFramePort.postMessage({
+        what: 'showDialog',
+        url: self.location.href,
+        netFilters: netFilterCandidates,
+        cosmeticFilters: cosmeticFilterCandidates,
+        filter: bestCandidateFilter,
+        options,
+    });
+};
+
+/******************************************************************************/
+
+const elementFromPoint = (( ) => {
+    let lastX, lastY;
+
+    return (x, y) => {
+        if ( x !== undefined ) {
+            lastX = x; lastY = y;
+        } else if ( lastX !== undefined ) {
+            x = lastX; y = lastY;
+        } else {
+            return null;
+        }
+        if ( !pickerFrame ) { return null; }
+        const magicAttr = `${pickerUniqueId}-clickblind`;
+        pickerFrame.setAttribute(magicAttr, '');
+        let elem = document.elementFromPoint(x, y);
+        if (
+            elem === null || /* to skip following tests */
+            elem === document.body ||
+            elem === document.documentElement || (
+                pickerBootArgs.zap !== true &&
+                noCosmeticFiltering &&
+                resourceURLsFromElement(elem).length === 0
+            )
+        ) {
+            elem = null;
+        }
+        // https://github.com/uBlockOrigin/uBlock-issues/issues/380
+        pickerFrame.removeAttribute(magicAttr);
+        return elem;
+    };
+})();
+
+/******************************************************************************/
+
+const highlightElementAtPoint = function(mx, my) {
+    const elem = elementFromPoint(mx, my);
+    highlightElements(elem ? [ elem ] : []);
+};
+
+/******************************************************************************/
+
+const filterElementAtPoint = function(mx, my, broad) {
+    if ( filtersFrom(mx, my) === 0 ) { return; }
+    showDialog({ broad });
+};
+
+/******************************************************************************/
+
+// https://www.reddit.com/r/uBlockOrigin/comments/bktxtb/scrolling_doesnt_work/emn901o
+//   Override 'fixed' position property on body element if present.
+
+// With touch-driven devices, first highlight the element and remove only
+// when tapping again the highlighted area.
+
+const zapElementAtPoint = function(mx, my, options) {
+    if ( options.highlight ) {
+        const elem = elementFromPoint(mx, my);
+        if ( elem ) {
+            highlightElements([ elem ]);
+        }
+        return;
+    }
+
+    let elemToRemove = targetElements.length !== 0 && targetElements[0] || null;
+    if ( elemToRemove === null && mx !== undefined ) {
+        elemToRemove = elementFromPoint(mx, my);
+    }
+
+    if ( elemToRemove instanceof Element === false ) { return; }
+
+    const getStyleValue = (elem, prop) => {
+        const style = window.getComputedStyle(elem);
+        return style ? style[prop] : '';
+    };
+
+    // Heuristic to detect scroll-locking: remove such lock when detected.
+    let maybeScrollLocked = elemToRemove.shadowRoot instanceof DocumentFragment;
+    if ( maybeScrollLocked === false ) {
+        let elem = elemToRemove;
+        do {
+            maybeScrollLocked =
+                parseInt(getStyleValue(elem, 'zIndex'), 10) >= 1000 ||
+                getStyleValue(elem, 'position') === 'fixed';
+            elem = elem.parentElement;
+        } while ( elem !== null && maybeScrollLocked === false );
+    }
+    if ( maybeScrollLocked ) {
+        const doc = document;
+        if ( getStyleValue(doc.body, 'overflowY') === 'hidden' ) {
+            doc.body.style.setProperty('overflow', 'auto', 'important');
+        }
+        if ( getStyleValue(doc.body, 'position') === 'fixed' ) {
+            doc.body.style.setProperty('position', 'initial', 'important');
+        }
+        if ( getStyleValue(doc.documentElement, 'position') === 'fixed' ) {
+            doc.documentElement.style.setProperty('position', 'initial', 'important');
+        }
+        if ( getStyleValue(doc.documentElement, 'overflowY') === 'hidden' ) {
+            doc.documentElement.style.setProperty('overflow', 'auto', 'important');
+        }
+    }
+    elemToRemove.remove();
+    highlightElementAtPoint(mx, my);
+};
+
+/******************************************************************************/
+
+const onKeyPressed = function(ev) {
+    // Delete
+    if (
+        (ev.key === 'Delete' || ev.key === 'Backspace') &&
+        pickerBootArgs.zap
+    ) {
+        ev.stopPropagation();
+        ev.preventDefault();
+        zapElementAtPoint();
+        return;
+    }
+    // Esc
+    if ( ev.key === 'Escape' || ev.which === 27 ) {
+        ev.stopPropagation();
+        ev.preventDefault();
+        filterToDOMInterface.preview(false);
+        quitPicker();
+        return;
+    }
+};
+
+/******************************************************************************/
+
+// https://github.com/chrisaljoudi/uBlock/issues/190
+//   May need to dynamically adjust the height of the overlay + new position
+//   of highlighted elements.
+
+const onViewportChanged = function() {
+    highlightElements(targetElements, true);
+};
+
+/******************************************************************************/
+
+// Auto-select a specific target, if any, and if possible
+
+const startPicker = function() {
+    pickerFrame.focus();
+
+    self.addEventListener('scroll', onViewportChanged, { passive: true });
+    self.addEventListener('resize', onViewportChanged, { passive: true });
+    self.addEventListener('keydown', onKeyPressed, true);
+
+    // Try using mouse position
+    if (
+        pickerBootArgs.mouse &&
+        vAPI.mouseClick instanceof Object &&
+        typeof vAPI.mouseClick.x === 'number' &&
+        vAPI.mouseClick.x > 0
+    ) {
+        if ( filtersFrom(vAPI.mouseClick.x, vAPI.mouseClick.y) !== 0 ) {
+            return showDialog();
+        }
+    }
+
+    // No mouse position available, use suggested target
+    const target = pickerBootArgs.target || '';
+    const pos = target.indexOf('\t');
+    if ( pos === -1 ) { return; }
+
+    const srcAttrMap = {
+        'a': 'href',
+        'audio': 'src',
+        'embed': 'src',
+        'iframe': 'src',
+        'img': 'src',
+        'video': 'src',
+    };
+    const tagName = target.slice(0, pos);
+    const url = target.slice(pos + 1);
+    const attr = srcAttrMap[tagName];
+    if ( attr === undefined ) { return; }
+    const elems = document.getElementsByTagName(tagName);
+    for ( const elem of elems  ) {
+        if ( elem === pickerFrame ) { continue; }
+        const srcs = resourceURLsFromElement(elem);
+        if (
+            (srcs.length !== 0 && srcs.includes(url) === false) ||
+            (srcs.length === 0 && url !== 'about:blank')
+        ) {
+            continue;
+        }
+        filtersFrom(elem);
+        if (
+            netFilterCandidates.length !== 0 ||
+            cosmeticFilterCandidates.length !== 0
+        ) {
+            if ( pickerBootArgs.mouse !== true ) {
+                elem.scrollIntoView({
+                    behavior: 'smooth',
+                    block: 'center',
+                    inline: 'center'
+                });
+            }
+            showDialog({ broad: true });
+        }
+        return;
+    }
+
+    // A target was specified, but it wasn't found: abort.
+    quitPicker();
+};
+
+/******************************************************************************/
+
+// Let's have the element picker code flushed from memory when no longer
+// in use: to ensure this, release all local references.
+
+const quitPicker = function() {
+    self.removeEventListener('scroll', onViewportChanged, { passive: true });
+    self.removeEventListener('resize', onViewportChanged, { passive: true });
+    self.removeEventListener('keydown', onKeyPressed, true);
+    vAPI.shutdown.remove(quitPicker);
+    if ( pickerFramePort ) {
+        pickerFramePort.close();
+        pickerFramePort = null;
+    }
+    if ( pickerFrame ) {
+        pickerFrame.remove();
+        pickerFrame = null;
+    }
+    vAPI.userStylesheet.remove(pickerCSS);
+    vAPI.userStylesheet.apply();
+    vAPI.pickerFrame = false;
+    self.focus();
+};
+
+vAPI.shutdown.add(quitPicker);
+
+/******************************************************************************/
+
+const onDialogMessage = function(msg) {
+    switch ( msg.what ) {
+        case 'start':
+            startPicker();
+            if ( pickerFramePort === null ) { break; }
+            if ( targetElements.length === 0 ) {
+                highlightElements([], true);
+            }
+            break;
+        case 'optimizeCandidates':
+            onOptimizeCandidates(msg);
+            break;
+        case 'dialogCreate':
+            filterToDOMInterface.queryAll(msg);
+            filterToDOMInterface.preview(true, true);
+            quitPicker();
+            break;
+        case 'dialogSetFilter': {
+            const resultset = filterToDOMInterface.queryAll(msg) || [];
+            highlightElements(resultset.map(a => a.elem), true);
+            if ( msg.filter === '!' ) { break; }
+            pickerFramePort.postMessage({
+                what: 'resultsetDetails',
+                count: resultset.length,
+                opt: resultset.length !== 0 ? resultset[0].opt : undefined,
+            });
+            break;
+        }
+        case 'quitPicker':
+            filterToDOMInterface.preview(false);
+            quitPicker();
+            break;
+        case 'highlightElementAtPoint':
+            highlightElementAtPoint(msg.mx, msg.my);
+            break;
+        case 'unhighlight':
+            highlightElements([]);
+            break;
+        case 'filterElementAtPoint':
+            filterElementAtPoint(msg.mx, msg.my, msg.broad);
+            break;
+        case 'zapElementAtPoint':
+            zapElementAtPoint(msg.mx, msg.my, msg.options);
+            if ( msg.options.highlight !== true && msg.options.stay !== true ) {
+                quitPicker();
+            }
+            break;
+        case 'togglePreview':
+            filterToDOMInterface.preview(msg.state);
+            if ( msg.state === false ) {
+                highlightElements(targetElements, true);
+            }
+            break;
+        default:
+            break;
+    }
+};
+
+/******************************************************************************/
+
+// epicker-ui.html will be injected in the page through an iframe, and
+// is a sandboxed so as to prevent the page from interfering with its
+// content and behavior.
+//
+// The purpose of epicker.js is to:
+// - Install the element picker UI, and wait for the component to establish
+//   a direct communication channel.
+// - Lookup candidate filters from elements at a specific position.
+// - Highlight element(s) at a specific position or according to whether
+//   they match candidate filters;
+// - Preview the result of applying a candidate filter;
+//
+// When the element picker is installed on a page, the only change the page
+// sees is an iframe with a random attribute. The page can't see the content
+// of the iframe, and cannot interfere with its style properties. However the
+// page can remove the iframe.
+
+// The DOM filterer will not be present when cosmetic filtering is disabled.
+const noCosmeticFiltering =
+    vAPI.domFilterer instanceof Object === false ||
+    vAPI.noSpecificCosmeticFiltering === true;
+
+// https://github.com/gorhill/uBlock/issues/1529
+//   In addition to inline styles, harden the element picker styles by using
+//   dedicated CSS rules.
+const pickerCSSStyle = [
+    'background: transparent',
+    'border: 0',
+    'border-radius: 0',
+    'box-shadow: none',
+    'color-scheme: light dark',
+    'display: block',
+    'filter: none',
+    'height: 100vh',
+    'left: 0',
+    'margin: 0',
+    'max-height: none',
+    'max-width: none',
+    'min-height: unset',
+    'min-width: unset',
+    'opacity: 1',
+    'outline: 0',
+    'padding: 0',
+    'pointer-events: auto',
+    'position: fixed',
+    'top: 0',
+    'transform: none',
+    'visibility: hidden',
+    'width: 100%',
+    'z-index: 2147483647',
+    ''
+].join(' !important;\n');
+
+
+const pickerCSS = `
+:root > [${pickerUniqueId}] {
+    ${pickerCSSStyle}
+}
+:root > [${pickerUniqueId}-loaded] {
+    visibility: visible !important;
+}
+:root [${pickerUniqueId}-clickblind] {
+    pointer-events: none !important;
+}
+`;
+
+vAPI.userStylesheet.add(pickerCSS);
+vAPI.userStylesheet.apply();
+
+let pickerBootArgs;
+let pickerFramePort = null;
+
+const bootstrap = async ( ) => {
+    pickerBootArgs = await vAPI.messaging.send('elementPicker', {
+        what: 'elementPickerArguments',
+    });
+    if ( typeof pickerBootArgs !== 'object' ) { return; }
+    if ( pickerBootArgs === null ) { return; }
+    // Restore net filter union data if origin is the same.
+    const eprom = pickerBootArgs.eprom || null;
+    if ( eprom !== null && eprom.lastNetFilterSession === lastNetFilterSession ) {
+        lastNetFilterHostname = eprom.lastNetFilterHostname || '';
+        lastNetFilterUnion = eprom.lastNetFilterUnion || '';
+    }
+    const url = new URL(pickerBootArgs.pickerURL);
+    if ( pickerBootArgs.zap ) {
+        url.searchParams.set('zap', '1');
+    }
+    return new Promise(resolve => {
+        const iframe = document.createElement('iframe');
+        iframe.setAttribute(pickerUniqueId, '');
+        document.documentElement.append(iframe);
+        iframe.addEventListener('load', ( ) => {
+            iframe.setAttribute(`${pickerUniqueId}-loaded`, '');
+            const channel = new MessageChannel();
+            pickerFramePort = channel.port1;
+            pickerFramePort.onmessage = ev => {
+                onDialogMessage(ev.data || {});
+            };
+            pickerFramePort.onmessageerror = ( ) => {
+                quitPicker();
+            };
+            iframe.contentWindow.postMessage(
+                { what: 'epickerStart' },
+                url.href,
+                [ channel.port2 ]
+            );
+            resolve(iframe);
+        }, { once: true });
+        iframe.contentWindow.location = url.href;
+    });
+};
+
+let pickerFrame = await bootstrap();
+if ( Boolean(pickerFrame) === false ) {
+    quitPicker();
+}
+
+/******************************************************************************/
+
+})();
+
+
+
+
+
+
+
+
+/*******************************************************************************
+
+    DO NOT:
+    - Remove the following code
+    - Add code beyond the following code
+    Reason:
+    - https://github.com/gorhill/uBlock/pull/3721
+    - uBO never uses the return value from injected content scripts
+
+**/
+
+void 0;
diff --git a/src/js/scriptlets/load-3p-css.js b/src/js/scriptlets/load-3p-css.js
new file mode 100644
index 0000000..bb7d542
--- /dev/null
+++ b/src/js/scriptlets/load-3p-css.js
@@ -0,0 +1,67 @@
+/*******************************************************************************
+
+    uBlock Origin - a comprehensive, efficient content blocker
+    Copyright (C) 2020-present Raymond Hill
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see {http://www.gnu.org/licenses/}.
+
+    Home: https://github.com/gorhill/uBlock
+*/
+
+'use strict';
+
+/******************************************************************************/
+
+(( ) => {
+    if ( typeof vAPI !== 'object' ) { return; }
+
+    if ( vAPI.dynamicReloadToken === undefined ) {
+        vAPI.dynamicReloadToken = vAPI.randomToken();
+    }
+
+    for ( const sheet of Array.from(document.styleSheets) ) {
+        let loaded = false;
+        try {
+            loaded = sheet.rules.length !== 0;
+        } catch(ex) {
+        }
+        if ( loaded ) { continue; }
+        const link = sheet.ownerNode || null;
+        if ( link === null || link.localName !== 'link' ) { continue; }
+        if ( link.hasAttribute(vAPI.dynamicReloadToken) ) { continue; }
+        const clone = link.cloneNode(true);
+        clone.setAttribute(vAPI.dynamicReloadToken, '');
+        link.replaceWith(clone);
+    }
+})();
+
+
+
+
+
+
+
+
+/*******************************************************************************
+
+    DO NOT:
+    - Remove the following code
+    - Add code beyond the following code
+    Reason:
+    - https://github.com/gorhill/uBlock/pull/3721
+    - uBO never uses the return value from injected content scripts
+
+**/
+
+void 0;
diff --git a/src/js/scriptlets/load-large-media-all.js b/src/js/scriptlets/load-large-media-all.js
new file mode 100644
index 0000000..a44539e
--- /dev/null
+++ b/src/js/scriptlets/load-large-media-all.js
@@ -0,0 +1,62 @@
+/*******************************************************************************
+
+    uBlock Origin - a comprehensive, efficient content blocker
+    Copyright (C) 2015-2018 Raymond Hill
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see {http://www.gnu.org/licenses/}.
+
+    Home: https://github.com/gorhill/uBlock
+*/
+
+'use strict';
+
+/******************************************************************************/
+
+(( ) => {
+
+/******************************************************************************/
+
+if (
+    typeof vAPI !== 'object' ||
+    vAPI.loadAllLargeMedia instanceof Function === false
+) {
+    return;
+}
+
+vAPI.loadAllLargeMedia();
+vAPI.loadAllLargeMedia = undefined;
+
+/******************************************************************************/
+
+})();
+
+
+
+
+
+
+
+
+/*******************************************************************************
+
+    DO NOT:
+    - Remove the following code
+    - Add code beyond the following code
+    Reason:
+    - https://github.com/gorhill/uBlock/pull/3721
+    - uBO never uses the return value from injected content scripts
+
+**/
+
+void 0;
diff --git a/src/js/scriptlets/load-large-media-interactive.js b/src/js/scriptlets/load-large-media-interactive.js
new file mode 100644
index 0000000..57198e4
--- /dev/null
+++ b/src/js/scriptlets/load-large-media-interactive.js
@@ -0,0 +1,299 @@
+/*******************************************************************************
+
+    uBlock Origin - a comprehensive, efficient content blocker
+    Copyright (C) 2015-present Raymond Hill
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see {http://www.gnu.org/licenses/}.
+
+    Home: https://github.com/gorhill/uBlock
+*/
+
+'use strict';
+
+/******************************************************************************/
+
+(( ) => {
+
+/******************************************************************************/
+
+// This can happen
+if ( typeof vAPI !== 'object' || vAPI.loadAllLargeMedia instanceof Function ) {
+    return;
+}
+
+/******************************************************************************/
+
+const largeMediaElementAttribute = 'data-' + vAPI.sessionId;
+const largeMediaElementSelector =
+    ':root   audio[' + largeMediaElementAttribute + '],\n' +
+    ':root     img[' + largeMediaElementAttribute + '],\n' +
+    ':root picture[' + largeMediaElementAttribute + '],\n' +
+    ':root   video[' + largeMediaElementAttribute + ']';
+
+/******************************************************************************/
+
+const isMediaElement = function(elem) {
+    return /^(?:audio|img|picture|video)$/.test(elem.localName);
+};
+
+/******************************************************************************/
+
+const mediaNotLoaded = function(elem) {
+    switch ( elem.localName ) {
+    case 'audio':
+    case 'video': {
+        const src = elem.src || '';
+        if ( src.startsWith('blob:') ) {
+            elem.autoplay = false;
+            elem.pause();
+        }
+        return elem.readyState === 0 || elem.error !== null;
+    }
+    case 'img': {
+        if ( elem.naturalWidth !== 0 || elem.naturalHeight !== 0 ) {
+            break;
+        }
+        const style = window.getComputedStyle(elem);
+        // For some reason, style can be null with Pale Moon.
+        return style !== null ?
+            style.getPropertyValue('display') !== 'none' :
+            elem.offsetHeight !== 0 && elem.offsetWidth !== 0;
+    }
+    default:
+        break;
+    }
+    return false;
+};
+
+/******************************************************************************/
+
+// For all media resources which have failed to load, trigger a reload.
+
+// <audio> and <video> elements.
+// https://developer.mozilla.org/en-US/docs/Web/API/HTMLMediaElement
+
+const surveyMissingMediaElements = function() {
+    let largeMediaElementCount = 0;
+    for ( const elem of document.querySelectorAll('audio,img,video') ) {
+        if ( mediaNotLoaded(elem) === false ) { continue; }
+        elem.setAttribute(largeMediaElementAttribute, '');
+        largeMediaElementCount += 1;
+        switch ( elem.localName ) {
+        case 'img': {
+            const picture = elem.closest('picture');
+            if ( picture !== null ) {
+                picture.setAttribute(largeMediaElementAttribute, '');
+            }
+        } break;
+        default:
+            break;
+        }
+    }
+    return largeMediaElementCount;
+};
+
+if ( surveyMissingMediaElements() === 0 ) { return; }
+
+// Insert CSS to highlight blocked media elements.
+if ( vAPI.largeMediaElementStyleSheet === undefined ) {
+    vAPI.largeMediaElementStyleSheet = [
+        largeMediaElementSelector + ' {',
+            'border: 2px dotted red !important;',
+            'box-sizing: border-box !important;',
+            'cursor: zoom-in !important;',
+            'display: inline-block;',
+            'filter: none !important;',
+            'font-size: 1rem !important;',
+            'min-height: 1em !important;',
+            'min-width: 1em !important;',
+            'opacity: 1 !important;',
+            'outline: none !important;',
+            'transform: none !important;',
+            'visibility: visible !important;',
+            'z-index: 2147483647',
+        '}',
+    ].join('\n');
+    vAPI.userStylesheet.add(vAPI.largeMediaElementStyleSheet);
+    vAPI.userStylesheet.apply();
+}
+
+/******************************************************************************/
+
+const loadMedia = async function(elem) {
+    const src = elem.getAttribute('src') || '';
+    elem.removeAttribute('src');
+
+    await vAPI.messaging.send('scriptlets', {
+        what: 'temporarilyAllowLargeMediaElement',
+    });
+
+    if ( src !== '' ) {
+        elem.setAttribute('src', src);
+    }
+    elem.load();
+};
+
+/******************************************************************************/
+
+const loadImage = async function(elem) {
+    const src = elem.getAttribute('src') || '';
+    elem.removeAttribute('src');
+
+    await vAPI.messaging.send('scriptlets', {
+        what: 'temporarilyAllowLargeMediaElement',
+    });
+
+    if ( src !== '' ) {
+        elem.setAttribute('src', src);
+    }
+};
+
+/******************************************************************************/
+
+const loadMany = function(elems) {
+    for ( const elem of elems ) {
+        switch ( elem.localName ) {
+        case 'audio':
+        case 'video':
+            loadMedia(elem);
+            break;
+        case 'img':
+            loadImage(elem);
+            break;
+        default:
+            break;
+        }
+    }
+};
+
+/******************************************************************************/
+
+const onMouseClick = function(ev) {
+    if ( ev.button !== 0 || ev.isTrusted === false ) { return; }
+
+    const toLoad = [];
+    const elems = document.elementsFromPoint instanceof Function
+        ? document.elementsFromPoint(ev.clientX, ev.clientY)
+        : [ ev.target ];
+    for ( const elem of elems ) {
+        if ( elem.matches(largeMediaElementSelector) === false ) { continue; }
+        elem.removeAttribute(largeMediaElementAttribute);
+        if ( mediaNotLoaded(elem) ) {
+            toLoad.push(elem);
+        }
+    }
+
+    if ( toLoad.length === 0 ) { return; }
+
+    loadMany(toLoad);
+
+    ev.preventDefault();
+    ev.stopPropagation();
+};
+
+document.addEventListener('click', onMouseClick, true);
+
+/******************************************************************************/
+
+const onLoadedData = function(ev) {
+    const media = ev.target;
+    if ( media.localName !== 'audio' && media.localName !== 'video' ) {
+        return;
+    }
+    const src = media.src;
+    if ( typeof src === 'string' && src.startsWith('blob:') === false ) {
+        return;
+    }
+    media.autoplay = false;
+    media.pause();
+};
+
+// https://www.reddit.com/r/uBlockOrigin/comments/mxgpmc/
+//   Support cases where the media source is not yet set.
+for ( const media of document.querySelectorAll('audio,video') ) {
+    const src = media.src;
+    if (
+        (typeof src === 'string') &&
+        (src === '' || src.startsWith('blob:'))
+    ) {
+        media.autoplay = false;
+        media.pause();
+    }
+}
+
+document.addEventListener('loadeddata', onLoadedData);
+
+/******************************************************************************/
+
+const onLoad = function(ev) {
+    const elem = ev.target;
+    if ( isMediaElement(elem) === false ) { return; }
+    elem.removeAttribute(largeMediaElementAttribute);
+};
+
+document.addEventListener('load', onLoad, true);
+
+/******************************************************************************/
+
+const onLoadError = function(ev) {
+    const elem = ev.target;
+    if ( isMediaElement(elem) === false ) { return; }
+    if ( mediaNotLoaded(elem) ) {
+        elem.setAttribute(largeMediaElementAttribute, '');
+    }
+};
+
+document.addEventListener('error', onLoadError, true);
+
+/******************************************************************************/
+
+vAPI.loadAllLargeMedia = function() {
+    document.removeEventListener('click', onMouseClick, true);
+    document.removeEventListener('loadeddata', onLoadedData, true);
+    document.removeEventListener('load', onLoad, true);
+    document.removeEventListener('error', onLoadError, true);
+
+    const toLoad = [];
+    for ( const elem of document.querySelectorAll(largeMediaElementSelector) ) {
+        elem.removeAttribute(largeMediaElementAttribute);
+        if ( mediaNotLoaded(elem) ) {
+            toLoad.push(elem);
+        }
+    }
+    loadMany(toLoad);
+};
+
+/******************************************************************************/
+
+})();
+
+
+
+
+
+
+
+
+/*******************************************************************************
+
+    DO NOT:
+    - Remove the following code
+    - Add code beyond the following code
+    Reason:
+    - https://github.com/gorhill/uBlock/pull/3721
+    - uBO never uses the return value from injected content scripts
+
+**/
+
+void 0;
diff --git a/src/js/scriptlets/noscript-spoof.js b/src/js/scriptlets/noscript-spoof.js
new file mode 100644
index 0000000..49e9093
--- /dev/null
+++ b/src/js/scriptlets/noscript-spoof.js
@@ -0,0 +1,89 @@
+/*******************************************************************************
+
+    uBlock Origin - a comprehensive, efficient content blocker
+    Copyright (C) 2014-present Raymond Hill
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see {http://www.gnu.org/licenses/}.
+
+    Home: https://github.com/gorhill/uBlock
+*/
+
+// Code below has been imported from uMatrix and modified to fit uBO:
+// https://github.com/gorhill/uMatrix/blob/3f8794dd899a05e066c24066c6c0a2515d5c60d2/src/js/contentscript.js#L464-L531
+
+'use strict';
+
+/******************************************************************************/
+
+// https://github.com/gorhill/uMatrix/issues/232
+//   Force `display` property, Firefox is still affected by the issue.
+
+(( ) => {
+    const noscripts = document.querySelectorAll('noscript');
+    if ( noscripts.length === 0 ) { return; }
+
+    const reMetaContent = /^\s*(\d+)\s*;\s*url=(?:"([^"]+)"|'([^']+)'|(.+))/i;
+    const reSafeURL = /^https?:\/\//;
+    let redirectTimer;
+
+    const autoRefresh = function(root) {
+        const meta = root.querySelector('meta[http-equiv="refresh"][content]');
+        if ( meta === null ) { return; }
+        const match = reMetaContent.exec(meta.getAttribute('content'));
+        if ( match === null ) { return; }
+        const refreshURL = (match[2] || match[3] || match[4] || '').trim();
+        let url;
+        try {
+            url = new URL(refreshURL, document.baseURI);
+        } catch(ex) {
+            return;
+        }
+        if ( reSafeURL.test(url.href) === false ) { return; }
+        redirectTimer = setTimeout(( ) => {
+                location.assign(url.href);
+            },
+            parseInt(match[1], 10) * 1000 + 1
+        );
+        meta.parentNode.removeChild(meta);
+    };
+
+    const morphNoscript = function(from) {
+        if ( /^application\/(?:xhtml\+)?xml/.test(document.contentType) ) {
+            const to = document.createElement('span');
+            while ( from.firstChild !== null ) {
+                to.appendChild(from.firstChild);
+            }
+            return to;
+        }
+        const parser = new DOMParser();
+        const doc = parser.parseFromString(
+            '<span>' + from.textContent + '</span>',
+            'text/html'
+        );
+        return document.adoptNode(doc.querySelector('span'));
+    };
+
+    for ( const noscript of noscripts ) {
+        const parent = noscript.parentNode;
+        if ( parent === null ) { continue; }
+        const span = morphNoscript(noscript);
+        span.style.setProperty('display', 'inline', 'important');
+        if ( redirectTimer === undefined ) {
+            autoRefresh(span);
+        }
+        parent.replaceChild(span, noscript);
+    }
+})();
+
+/******************************************************************************/
diff --git a/src/js/scriptlets/should-inject-contentscript.js b/src/js/scriptlets/should-inject-contentscript.js
new file mode 100644
index 0000000..b9a2658
--- /dev/null
+++ b/src/js/scriptlets/should-inject-contentscript.js
@@ -0,0 +1,40 @@
+/*******************************************************************************
+
+    uBlock Origin - a comprehensive, efficient content blocker
+    Copyright (C) 2018-present Raymond Hill
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see {http://www.gnu.org/licenses/}.
+
+    Home: https://github.com/gorhill/uBlock
+*/
+
+'use strict';
+
+// If content scripts are already injected, we need to respond with `false`,
+// to "should inject content scripts?"
+//
+// https://github.com/uBlockOrigin/uBlock-issues/issues/403
+//   If the content script was not bootstrapped, give it another try.
+
+(( ) => {
+    try {
+        let status = vAPI.uBO !== true;
+        if ( status === false && vAPI.bootstrap ) {
+            self.requestIdleCallback(( ) => vAPI && vAPI.bootstrap());
+        }
+        return status;
+    } catch(ex) {
+    }
+    return true;
+})();
diff --git a/src/js/scriptlets/subscriber.js b/src/js/scriptlets/subscriber.js
new file mode 100644
index 0000000..ea7b209
--- /dev/null
+++ b/src/js/scriptlets/subscriber.js
@@ -0,0 +1,113 @@
+/*******************************************************************************
+
+    uBlock Origin - a comprehensive, efficient content blocker
+    Copyright (C) 2015-present Raymond Hill
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see {http://www.gnu.org/licenses/}.
+
+    Home: https://github.com/gorhill/uBlock
+*/
+
+/* global HTMLDocument */
+
+'use strict';
+
+/******************************************************************************/
+
+// Injected into specific web pages, those which have been pre-selected
+// because they are known to contains `abp:subscribe` links.
+
+/******************************************************************************/
+
+(( ) => {
+// >>>>> start of local scope
+
+/******************************************************************************/
+
+// https://github.com/chrisaljoudi/uBlock/issues/464
+if ( document instanceof HTMLDocument === false ) { return; }
+
+// Maybe uBO has gone away meanwhile.
+if ( typeof vAPI !== 'object' || vAPI === null ) { return; }
+
+const onMaybeSubscriptionLinkClicked = function(target) {
+    if ( vAPI instanceof Object === false ) {
+        document.removeEventListener('click', onMaybeSubscriptionLinkClicked);
+        return;
+    }
+
+    try {
+        // https://github.com/uBlockOrigin/uBlock-issues/issues/763#issuecomment-691696716
+        //   Remove replacement patch if/when filterlists.com fixes encoded '&'.
+        const subscribeURL = new URL(
+            target.href.replace('&amp;title=', '&title=')
+        );
+        if (
+            /^(abp|ubo):$/.test(subscribeURL.protocol) === false &&
+            subscribeURL.hostname !== 'subscribe.adblockplus.org'
+        ) {
+            return;
+        }
+        const location = subscribeURL.searchParams.get('location') || '';
+        const title = subscribeURL.searchParams.get('title') || '';
+        if ( location === '' || title === '' ) { return true; }
+        // https://github.com/uBlockOrigin/uBlock-issues/issues/1797
+        if ( /^(file|https?):\/\//.test(location) === false ) { return true; }
+        vAPI.messaging.send('scriptlets', {
+            what: 'subscribeTo',
+            location,
+            title,
+        });
+        return true;
+    } catch (_) {
+    }
+};
+
+// https://github.com/easylist/EasyListHebrew/issues/89
+//   Ensure trusted events only.
+
+document.addEventListener('click', ev => {
+    if ( ev.button !== 0 || ev.isTrusted === false ) { return; }
+    const target = ev.target.closest('a');
+    if ( target instanceof HTMLAnchorElement === false ) { return; }
+    if ( onMaybeSubscriptionLinkClicked(target) === true ) {
+        ev.stopPropagation();
+        ev.preventDefault();
+    }
+});
+
+/******************************************************************************/
+
+// <<<<< end of local scope
+})();
+
+
+
+
+
+
+
+
+/*******************************************************************************
+
+    DO NOT:
+    - Remove the following code
+    - Add code beyond the following code
+    Reason:
+    - https://github.com/gorhill/uBlock/pull/3721
+    - uBO never uses the return value from injected content scripts
+
+**/
+
+void 0;
diff --git a/src/js/scriptlets/updater.js b/src/js/scriptlets/updater.js
new file mode 100644
index 0000000..006b663
--- /dev/null
+++ b/src/js/scriptlets/updater.js
@@ -0,0 +1,118 @@
+/*******************************************************************************
+
+    uBlock Origin - a comprehensive, efficient content blocker
+    Copyright (C) 2014-present Raymond Hill
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see {http://www.gnu.org/licenses/}.
+
+    Home: https://github.com/gorhill/uBlock
+*/
+
+/* global HTMLDocument */
+
+'use strict';
+
+/******************************************************************************/
+
+// Injected into specific webpages, those which have been pre-selected
+// because they are known to contain:
+// https://ublockorigin.github.io/uAssets/update-lists?listkeys=[...]
+
+/******************************************************************************/
+
+(( ) => {
+// >>>>> start of local scope
+
+/******************************************************************************/
+
+if ( document instanceof HTMLDocument === false ) { return; }
+
+// Maybe uBO has gone away meanwhile.
+if ( typeof vAPI !== 'object' || vAPI === null ) { return; }
+
+function updateStockLists(target) {
+    if ( vAPI instanceof Object === false ) {
+        document.removeEventListener('click', updateStockLists);
+        return;
+    }
+    try {
+        const updateURL = new URL(target.href);
+        if ( updateURL.hostname !== 'ublockorigin.github.io') { return; }
+        if ( updateURL.pathname !== '/uAssets/update-lists.html') { return; }
+        const listkeys = updateURL.searchParams.get('listkeys') || '';
+        if ( listkeys === '' ) { return; }
+        let auto = true;
+        const manual = updateURL.searchParams.get('manual');
+        if ( manual === '1' ) {
+            auto = false;
+        } else if ( /^\d{6}$/.test(`${manual}`) ) {
+            const year = parseInt(manual.slice(0,2)) || 0;
+            const month = parseInt(manual.slice(2,4)) || 0;
+            const day = parseInt(manual.slice(4,6)) || 0;
+            if ( year !== 0 && month !== 0 && day !== 0 ) {
+                const date = new Date();
+                date.setUTCFullYear(2000 + year, month - 1, day);
+                date.setUTCHours(0);
+                const then = date.getTime() / 1000 / 3600;
+                const now = Date.now() / 1000 / 3600;
+                auto = then < (now - 48) || then > (now + 48);
+            }
+        }
+        vAPI.messaging.send('scriptlets', {
+            what: 'updateLists',
+            listkeys,
+            auto,
+        });
+        return true;
+    } catch (_) {
+    }
+}
+
+// https://github.com/easylist/EasyListHebrew/issues/89
+//   Ensure trusted events only.
+
+document.addEventListener('click', ev => {
+    if ( ev.button !== 0 || ev.isTrusted === false ) { return; }
+    const target = ev.target.closest('a');
+    if ( target instanceof HTMLAnchorElement === false ) { return; }
+    if ( updateStockLists(target) === true ) {
+        ev.stopPropagation();
+        ev.preventDefault();
+    }
+});
+
+/******************************************************************************/
+
+// <<<<< end of local scope
+})();
+
+
+
+
+
+
+
+
+/*******************************************************************************
+
+    DO NOT:
+    - Remove the following code
+    - Add code beyond the following code
+    Reason:
+    - https://github.com/gorhill/uBlock/pull/3721
+    - uBO never uses the return value from injected content scripts
+
+**/
+
+void 0;