Adding upstream version 126.0.upstream/126.0

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

41 files changed, 1174 insertions, 2384 deletions

diff --git a/browser/components/asrouter/.eslintrc.js b/browser/components/asrouter/.eslintrc.js
index ef5bc81b68..b2a647e42d 100644
--- a/browser/components/asrouter/.eslintrc.js
+++ b/browser/components/asrouter/.eslintrc.js
@@ -63,8 +63,6 @@ module.exports = {
     },
   ],
   rules: {
-    "fetch-options/no-fetch-credentials": "error",
-
     "react/jsx-boolean-value": ["error", "always"],
     "react/jsx-key": "error",
     "react/jsx-no-bind": [
diff --git a/browser/components/asrouter/actors/ASRouterChild.sys.mjs b/browser/components/asrouter/actors/ASRouterChild.sys.mjs
index 2096d92bb3..95f625e2b5 100644
--- a/browser/components/asrouter/actors/ASRouterChild.sys.mjs
+++ b/browser/components/asrouter/actors/ASRouterChild.sys.mjs
@@ -11,9 +11,7 @@
 
 // eslint-disable-next-line mozilla/use-static-import
 const { MESSAGE_TYPE_LIST, MESSAGE_TYPE_HASH: msg } =
-  ChromeUtils.importESModule(
-    "resource:///modules/asrouter/ActorConstants.sys.mjs"
-  );
+  ChromeUtils.importESModule("resource:///modules/asrouter/ActorConstants.mjs");
 
 const VALID_TYPES = new Set(MESSAGE_TYPE_LIST);
 
@@ -103,8 +101,6 @@ export class ASRouterChild extends JSWindowActorChild {
         case msg.DISABLE_PROVIDER:
         case msg.ENABLE_PROVIDER:
         case msg.EXPIRE_QUERY_CACHE:
-        case msg.FORCE_WHATSNEW_PANEL:
-        case msg.CLOSE_WHATSNEW_PANEL:
         case msg.FORCE_PRIVATE_BROWSING_WINDOW:
         case msg.IMPRESSION:
         case msg.RESET_PROVIDER_PREF:
diff --git a/browser/components/asrouter/bin/import-rollouts.js b/browser/components/asrouter/bin/import-rollouts.js
index d29a31a068..bb5c17d9ae 100644
--- a/browser/components/asrouter/bin/import-rollouts.js
+++ b/browser/components/asrouter/bin/import-rollouts.js
@@ -126,10 +126,6 @@ async function getMessageValidators(skipValidation) {
       "./content-src/templates/OnboardingMessage/UpdateAction.schema.json",
       { common: true }
     ),
-    whatsnew_panel_message: await getValidator(
-      "./content-src/templates/OnboardingMessage/WhatsNewMessage.schema.json",
-      { common: true }
-    ),
     feature_callout: await getValidator(
       // For now, Feature Callout and Spotlight share a common schema
       "./content-src/templates/OnboardingMessage/Spotlight.schema.json",
diff --git a/browser/components/asrouter/content-src/asrouter-utils.mjs b/browser/components/asrouter/content-src/asrouter-utils.mjs
index 989d864e71..3789158547 100644
--- a/browser/components/asrouter/content-src/asrouter-utils.mjs
+++ b/browser/components/asrouter/content-src/asrouter-utils.mjs
@@ -2,10 +2,8 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-// eslint-disable-next-line mozilla/reject-import-system-module-from-non-system
-import { MESSAGE_TYPE_HASH as msg } from "../modules/ActorConstants.sys.mjs";
-// eslint-disable-next-line mozilla/reject-import-system-module-from-non-system
-import { actionCreators as ac } from "../../newtab/common/Actions.sys.mjs";
+import { MESSAGE_TYPE_HASH as msg } from "../modules/ActorConstants.mjs";
+import { actionCreators as ac } from "../../newtab/common/Actions.mjs";
 
 export const ASRouterUtils = {
   addListener(listener) {
diff --git a/browser/components/asrouter/content-src/components/ASRouterAdmin/ASRouterAdmin.jsx b/browser/components/asrouter/content-src/components/ASRouterAdmin/ASRouterAdmin.jsx
index befce707ef..32d1614307 100644
--- a/browser/components/asrouter/content-src/components/ASRouterAdmin/ASRouterAdmin.jsx
+++ b/browser/components/asrouter/content-src/components/ASRouterAdmin/ASRouterAdmin.jsx
@@ -15,6 +15,18 @@ const Row = props => (
   </tr>
 );
 
+// Convert a UTF-8 string to a string in which only one byte of each
+// 16-bit unit is occupied. This is necessary to comply with `btoa` API constraints.
+export function toBinary(string) {
+  const codeUnits = new Uint16Array(string.length);
+  for (let i = 0; i < codeUnits.length; i++) {
+    codeUnits[i] = string.charCodeAt(i);
+  }
+  return btoa(
+    String.fromCharCode(...Array.from(new Uint8Array(codeUnits.buffer)))
+  );
+}
+
 function relativeTime(timestamp) {
   if (!timestamp) {
     return "";
@@ -531,7 +543,9 @@ export class ASRouterAdminInner extends React.PureComponent {
           {aboutMessagePreviewSupported ? (
             <CopyButton
               transformer={text =>
-                `about:messagepreview?json=${encodeURIComponent(btoa(text))}`
+                `about:messagepreview?json=${encodeURIComponent(
+                  toBinary(text)
+                )}`
               }
               label="Share"
               copiedLabel="Copied!"
diff --git a/browser/components/asrouter/content-src/schemas/BackgroundTaskMessagingExperiment.schema.json b/browser/components/asrouter/content-src/schemas/BackgroundTaskMessagingExperiment.schema.json
index 9de01052f7..5fe86f9617 100644
--- a/browser/components/asrouter/content-src/schemas/BackgroundTaskMessagingExperiment.schema.json
+++ b/browser/components/asrouter/content-src/schemas/BackgroundTaskMessagingExperiment.schema.json
@@ -10,7 +10,9 @@
         "const": "multi"
       }
     },
-    "required": ["template"]
+    "required": [
+      "template"
+    ]
   },
   "then": {
     "$ref": "chrome://browser/content/asrouter/schemas/BackgroundTaskMessagingExperiment.schema.json#/$defs/MultiMessage"
@@ -68,7 +70,9 @@
                   "type": "object"
                 }
               },
-              "required": ["type"],
+              "required": [
+                "type"
+              ],
               "additionalProperties": true
             },
             "requireInteraction": {
@@ -116,24 +120,37 @@
                         "type": "object"
                       }
                     },
-                    "required": ["type"],
+                    "required": [
+                      "type"
+                    ],
                     "additionalProperties": true
                   }
                 },
-                "required": ["action", "title"],
+                "required": [
+                  "action",
+                  "title"
+                ],
                 "additionalProperties": true
               }
             }
           },
           "additionalProperties": true,
-          "required": ["title", "body"]
+          "required": [
+            "title",
+            "body"
+          ]
         },
         "template": {
           "type": "string",
           "const": "toast_notification"
         }
       },
-      "required": ["content", "targeting", "template", "trigger"],
+      "required": [
+        "content",
+        "targeting",
+        "template",
+        "trigger"
+      ],
       "additionalProperties": true
     },
     "Message": {
@@ -154,7 +171,9 @@
         "template": {
           "type": "string",
           "description": "Which messaging template this message is using.",
-          "enum": ["toast_notification"]
+          "enum": [
+            "toast_notification"
+          ]
         },
         "frequency": {
           "type": "object",
@@ -184,7 +203,10 @@
                     "maximum": 100
                   }
                 },
-                "required": ["period", "cap"]
+                "required": [
+                  "period",
+                  "cap"
+                ]
               }
             }
           }
@@ -224,7 +246,9 @@
               }
             }
           },
-          "required": ["id"]
+          "required": [
+            "id"
+          ]
         },
         "provider": {
           "description": "An identifier for the provider of this message, such as \"cfr\" or \"preview\".",
@@ -233,8 +257,14 @@
       },
       "additionalProperties": true,
       "dependentRequired": {
-        "content": ["id", "template"],
-        "template": ["id", "content"]
+        "content": [
+          "id",
+          "template"
+        ],
+        "template": [
+          "id",
+          "content"
+        ]
       }
     },
     "localizedText": {
@@ -245,7 +275,9 @@
           "type": "string"
         }
       },
-      "required": ["string_id"]
+      "required": [
+        "string_id"
+      ]
     },
     "localizableText": {
       "description": "Either a raw string or an object containing the string_id of the localized text",
@@ -272,10 +304,14 @@
             "properties": {
               "template": {
                 "type": "string",
-                "enum": ["toast_notification"]
+                "enum": [
+                  "toast_notification"
+                ]
               }
             },
-            "required": ["template"]
+            "required": [
+              "template"
+            ]
           },
           "then": {
             "$ref": "chrome://browser/content/asrouter/schemas/BackgroundTaskMessagingExperiment.schema.json#/$defs/ToastNotification"
@@ -299,7 +335,10 @@
           }
         }
       },
-      "required": ["template", "messages"]
+      "required": [
+        "template",
+        "messages"
+      ]
     }
   }
 }
diff --git a/browser/components/asrouter/content-src/schemas/MessagingExperiment.schema.json b/browser/components/asrouter/content-src/schemas/MessagingExperiment.schema.json
index fbabb109f8..dd4ce4776d 100644
--- a/browser/components/asrouter/content-src/schemas/MessagingExperiment.schema.json
+++ b/browser/components/asrouter/content-src/schemas/MessagingExperiment.schema.json
@@ -10,7 +10,9 @@
         "const": "multi"
       }
     },
-    "required": ["template"]
+    "required": [
+      "template"
+    ]
   },
   "then": {
     "$ref": "chrome://browser/content/asrouter/schemas/MessagingExperiment.schema.json#/$defs/MultiMessage"
@@ -41,7 +43,9 @@
             "layout": {
               "type": "string",
               "description": "Describes how content should be displayed.",
-              "enum": ["chiclet_open_url"]
+              "enum": [
+                "chiclet_open_url"
+              ]
             },
             "bucket_id": {
               "type": "string",
@@ -66,11 +70,17 @@
                 "where": {
                   "description": "Should it open in a new tab or the current tab",
                   "type": "string",
-                  "enum": ["current", "tabshifted"]
+                  "enum": [
+                    "current",
+                    "tabshifted"
+                  ]
                 }
               },
               "additionalProperties": true,
-              "required": ["url", "where"]
+              "required": [
+                "url",
+                "where"
+              ]
             }
           },
           "additionalProperties": true,
@@ -87,7 +97,10 @@
           "const": "cfr_urlbar_chiclet"
         }
       },
-      "required": ["targeting", "trigger"]
+      "required": [
+        "targeting",
+        "trigger"
+      ]
     },
     "ExtensionDoorhanger": {
       "$schema": "https://json-schema.org/draft/2019-09/schema",
@@ -162,10 +175,14 @@
                               "description": "Text for button tooltip used to provide information about the doorhanger."
                             }
                           },
-                          "required": ["tooltiptext"]
+                          "required": [
+                            "tooltiptext"
+                          ]
                         }
                       },
-                      "required": ["attributes"]
+                      "required": [
+                        "attributes"
+                      ]
                     },
                     {
                       "$ref": "chrome://browser/content/asrouter/schemas/MessagingExperiment.schema.json#/$defs/localizedText"
@@ -185,7 +202,10 @@
             "learn_more": {
               "type": "string",
               "description": "Last part of the path in the SUMO URL to the support page with the information about the doorhanger.",
-              "examples": ["extensionpromotions", "extensionrecommendations"]
+              "examples": [
+                "extensionpromotions",
+                "extensionrecommendations"
+              ]
             },
             "heading_text": {
               "$ref": "chrome://browser/content/asrouter/schemas/MessagingExperiment.schema.json#/$defs/localizableText",
@@ -236,7 +256,12 @@
                   "description": "Link that offers more information related to the addon."
                 }
               },
-              "required": ["title", "author", "icon", "amo_url"]
+              "required": [
+                "title",
+                "author",
+                "icon",
+                "amo_url"
+              ]
             },
             "text": {
               "$ref": "chrome://browser/content/asrouter/schemas/MessagingExperiment.schema.json#/$defs/localizableText",
@@ -255,7 +280,9 @@
                   }
                 }
               },
-              "required": ["steps"]
+              "required": [
+                "steps"
+              ]
             },
             "buttons": {
               "description": "The label and functionality for the buttons in the pop-over.",
@@ -281,11 +308,16 @@
                                   "description": "A single character to be used as a shortcut key for the secondary button. This should be one of the characters that appears in the button label."
                                 }
                               },
-                              "required": ["accesskey"],
+                              "required": [
+                                "accesskey"
+                              ],
                               "description": "Button attributes."
                             }
                           },
-                          "required": ["value", "attributes"]
+                          "required": [
+                            "value",
+                            "attributes"
+                          ]
                         },
                         {
                           "$ref": "chrome://browser/content/asrouter/schemas/MessagingExperiment.schema.json#/$defs/localizedText"
@@ -341,11 +373,16 @@
                                     "description": "A single character to be used as a shortcut key for the secondary button. This should be one of the characters that appears in the button label."
                                   }
                                 },
-                                "required": ["accesskey"],
+                                "required": [
+                                  "accesskey"
+                                ],
                                 "description": "Button attributes."
                               }
                             },
-                            "required": ["value", "attributes"]
+                            "required": [
+                              "value",
+                              "attributes"
+                            ]
                           },
                           {
                             "properties": {
@@ -360,7 +397,9 @@
                                 ]
                               }
                             },
-                            "required": ["string_id"]
+                            "required": [
+                              "string_id"
+                            ]
                           }
                         ],
                         "description": "Id of localized string or message override."
@@ -417,16 +456,25 @@
             }
           },
           "then": {
-            "required": ["category", "notification_text"]
+            "required": [
+              "category",
+              "notification_text"
+            ]
           }
         },
         "template": {
           "type": "string",
-          "enum": ["cfr_doorhanger", "milestone_message"]
+          "enum": [
+            "cfr_doorhanger",
+            "milestone_message"
+          ]
         }
       },
       "additionalProperties": true,
-      "required": ["targeting", "trigger"],
+      "required": [
+        "targeting",
+        "trigger"
+      ],
       "$defs": {
         "plainText": {
           "description": "Plain text (no HTML allowed)",
@@ -457,7 +505,10 @@
             "type": {
               "type": "string",
               "description": "Should the message be global (persisted across tabs) or local (disappear when switching to a different tab).",
-              "enum": ["global", "tab"]
+              "enum": [
+                "global",
+                "tab"
+              ]
             },
             "text": {
               "$ref": "chrome://browser/content/asrouter/schemas/MessagingExperiment.schema.json#/$defs/localizableText",
@@ -497,7 +548,9 @@
                         "type": "object"
                       }
                     },
-                    "required": ["type"],
+                    "required": [
+                      "type"
+                    ],
                     "additionalProperties": true
                   },
                   "supportPage": {
@@ -505,13 +558,19 @@
                     "description": "A page title on SUMO to link to"
                   }
                 },
-                "required": ["label", "action"],
+                "required": [
+                  "label",
+                  "action"
+                ],
                 "additionalProperties": true
               }
             }
           },
           "additionalProperties": true,
-          "required": ["text", "buttons"]
+          "required": [
+            "text",
+            "buttons"
+          ]
         },
         "template": {
           "type": "string",
@@ -519,7 +578,10 @@
         }
       },
       "additionalProperties": true,
-      "required": ["targeting", "trigger"],
+      "required": [
+        "targeting",
+        "trigger"
+      ],
       "$defs": {
         "plainText": {
           "description": "Plain text (no HTML allowed)",
@@ -587,12 +649,22 @@
             "promoType": {
               "type": "string",
               "description": "Promo type used to determine if promo should show to a given user",
-              "enum": ["FOCUS", "VPN", "PIN", "COOKIE_BANNERS", "OTHER"]
+              "enum": [
+                "FOCUS",
+                "VPN",
+                "PIN",
+                "COOKIE_BANNERS",
+                "OTHER"
+              ]
             },
             "promoSectionStyle": {
               "type": "string",
               "description": "Sets the position of the promo section. Possible values are: top, below-search, bottom. Default bottom.",
-              "enum": ["top", "below-search", "bottom"]
+              "enum": [
+                "top",
+                "below-search",
+                "bottom"
+              ]
             },
             "promoTitle": {
               "type": "string",
@@ -624,16 +696,23 @@
                       "type": "object"
                     }
                   },
-                  "required": ["type"],
+                  "required": [
+                    "type"
+                  ],
                   "additionalProperties": true
                 }
               },
-              "required": ["action"]
+              "required": [
+                "action"
+              ]
             },
             "promoLinkType": {
               "type": "string",
               "description": "Type of promo link type. Possible values: link, button. Default is link.",
-              "enum": ["link", "button"]
+              "enum": [
+                "link",
+                "button"
+              ]
             },
             "promoImageLarge": {
               "type": "string",
@@ -655,10 +734,14 @@
                     "const": true
                   }
                 },
-                "required": ["promoEnabled"]
+                "required": [
+                  "promoEnabled"
+                ]
               },
               "then": {
-                "required": ["promoButton"]
+                "required": [
+                  "promoButton"
+                ]
               }
             },
             {
@@ -668,20 +751,28 @@
                     "const": true
                   }
                 },
-                "required": ["infoEnabled"]
+                "required": [
+                  "infoEnabled"
+                ]
               },
               "then": {
-                "required": ["infoLinkText"],
+                "required": [
+                  "infoLinkText"
+                ],
                 "if": {
                   "properties": {
                     "infoTitleEnabled": {
                       "const": true
                     }
                   },
-                  "required": ["infoTitleEnabled"]
+                  "required": [
+                    "infoTitleEnabled"
+                  ]
                 },
                 "then": {
-                  "required": ["infoTitle"]
+                  "required": [
+                    "infoTitle"
+                  ]
                 }
               }
             }
@@ -693,7 +784,9 @@
         }
       },
       "additionalProperties": true,
-      "required": ["targeting"]
+      "required": [
+        "targeting"
+      ]
     },
     "Spotlight": {
       "$schema": "https://json-schema.org/draft/2019-09/schema",
@@ -763,11 +856,16 @@
         "template": {
           "type": "string",
           "description": "Specify whether the surface is shown as a Spotlight modal or an in-surface Feature Callout dialog",
-          "enum": ["spotlight", "feature_callout"]
+          "enum": [
+            "spotlight",
+            "feature_callout"
+          ]
         }
       },
       "additionalProperties": true,
-      "required": ["targeting"]
+      "required": [
+        "targeting"
+      ]
     },
     "ToastNotification": {
       "$schema": "https://json-schema.org/draft/2019-09/schema",
@@ -818,7 +916,9 @@
                   "type": "object"
                 }
               },
-              "required": ["type"],
+              "required": [
+                "type"
+              ],
               "additionalProperties": true
             },
             "requireInteraction": {
@@ -866,24 +966,37 @@
                         "type": "object"
                       }
                     },
-                    "required": ["type"],
+                    "required": [
+                      "type"
+                    ],
                     "additionalProperties": true
                   }
                 },
-                "required": ["action", "title"],
+                "required": [
+                  "action",
+                  "title"
+                ],
                 "additionalProperties": true
               }
             }
           },
           "additionalProperties": true,
-          "required": ["title", "body"]
+          "required": [
+            "title",
+            "body"
+          ]
         },
         "template": {
           "type": "string",
           "const": "toast_notification"
         }
       },
-      "required": ["content", "targeting", "template", "trigger"],
+      "required": [
+        "content",
+        "targeting",
+        "template",
+        "trigger"
+      ],
       "additionalProperties": true
     },
     "ToolbarBadgeMessage": {
@@ -912,7 +1025,9 @@
                 }
               },
               "additionalProperties": true,
-              "required": ["id"],
+              "required": [
+                "id"
+              ],
               "description": "Optional action to take in addition to showing the notification"
             },
             "delay": {
@@ -925,7 +1040,9 @@
             }
           },
           "additionalProperties": true,
-          "required": ["target"]
+          "required": [
+            "target"
+          ]
         },
         "template": {
           "type": "string",
@@ -933,7 +1050,9 @@
         }
       },
       "additionalProperties": true,
-      "required": ["targeting"]
+      "required": [
+        "targeting"
+      ]
     },
     "UpdateAction": {
       "$schema": "https://json-schema.org/draft/2019-09/schema",
@@ -973,101 +1092,25 @@
               },
               "additionalProperties": true,
               "description": "Optional action to take in addition to showing the notification",
-              "required": ["id", "data"]
-            }
-          },
-          "additionalProperties": true,
-          "required": ["action"]
-        },
-        "template": {
-          "type": "string",
-          "const": "update_action"
-        }
-      },
-      "required": ["targeting"]
-    },
-    "WhatsNewMessage": {
-      "$schema": "https://json-schema.org/draft/2019-09/schema",
-      "$id": "file:///WhatsNewMessage.schema.json",
-      "title": "WhatsNewMessage",
-      "description": "A template for the messages that appear in the What's New panel.",
-      "allOf": [
-        {
-          "$ref": "chrome://browser/content/asrouter/schemas/MessagingExperiment.schema.json#/$defs/Message"
-        }
-      ],
-      "type": "object",
-      "properties": {
-        "content": {
-          "type": "object",
-          "properties": {
-            "layout": {
-              "description": "Different message layouts",
-              "enum": ["tracking-protections"]
-            },
-            "bucket_id": {
-              "type": "string",
-              "description": "A bucket identifier for the addon. This is used in order to anonymize telemetry for history-sensitive targeting."
-            },
-            "published_date": {
-              "type": "integer",
-              "description": "The date/time (number of milliseconds elapsed since January 1, 1970 00:00:00 UTC) the message was published."
-            },
-            "title": {
-              "$ref": "chrome://browser/content/asrouter/schemas/MessagingExperiment.schema.json#/$defs/localizableText",
-              "description": "Id of localized string or message override of What's New message title"
-            },
-            "subtitle": {
-              "$ref": "chrome://browser/content/asrouter/schemas/MessagingExperiment.schema.json#/$defs/localizableText",
-              "description": "Id of localized string or message override of What's New message subtitle"
-            },
-            "body": {
-              "$ref": "chrome://browser/content/asrouter/schemas/MessagingExperiment.schema.json#/$defs/localizableText",
-              "description": "Id of localized string or message override of What's New message body"
-            },
-            "link_text": {
-              "$ref": "chrome://browser/content/asrouter/schemas/MessagingExperiment.schema.json#/$defs/localizableText",
-              "description": "(optional) Id of localized string or message override of What's New message link text"
-            },
-            "cta_url": {
-              "description": "Target URL for the What's New message.",
-              "type": "string",
-              "format": "moz-url-format"
-            },
-            "cta_type": {
-              "description": "Type of url open action",
-              "enum": ["OPEN_URL", "OPEN_ABOUT_PAGE", "OPEN_PROTECTION_REPORT"]
-            },
-            "cta_where": {
-              "description": "How to open the cta: new window, tab, focused, unfocused.",
-              "enum": ["current", "tabshifted", "tab", "save", "window"]
-            },
-            "icon_url": {
-              "description": "(optional) URL for the What's New message icon.",
-              "type": "string",
-              "format": "uri"
-            },
-            "icon_alt": {
-              "$ref": "chrome://browser/content/asrouter/schemas/MessagingExperiment.schema.json#/$defs/localizableText",
-              "description": "Alt text for image."
+              "required": [
+                "id",
+                "data"
+              ]
             }
           },
           "additionalProperties": true,
           "required": [
-            "published_date",
-            "title",
-            "body",
-            "cta_url",
-            "bucket_id"
+            "action"
           ]
         },
         "template": {
           "type": "string",
-          "const": "whatsnew_panel_message"
+          "const": "update_action"
         }
       },
-      "required": ["order"],
-      "additionalProperties": true
+      "required": [
+        "targeting"
+      ]
     },
     "Message": {
       "type": "object",
@@ -1097,8 +1140,7 @@
             "feature_callout",
             "toast_notification",
             "toolbar_badge",
-            "update_action",
-            "whatsnew_panel_message"
+            "update_action"
           ]
         },
         "frequency": {
@@ -1129,7 +1171,10 @@
                     "maximum": 100
                   }
                 },
-                "required": ["period", "cap"]
+                "required": [
+                  "period",
+                  "cap"
+                ]
               }
             }
           }
@@ -1169,7 +1214,9 @@
               }
             }
           },
-          "required": ["id"]
+          "required": [
+            "id"
+          ]
         },
         "provider": {
           "description": "An identifier for the provider of this message, such as \"cfr\" or \"preview\".",
@@ -1178,8 +1225,14 @@
       },
       "additionalProperties": true,
       "dependentRequired": {
-        "content": ["id", "template"],
-        "template": ["id", "content"]
+        "content": [
+          "id",
+          "template"
+        ],
+        "template": [
+          "id",
+          "content"
+        ]
       }
     },
     "localizedText": {
@@ -1190,7 +1243,9 @@
           "type": "string"
         }
       },
-      "required": ["string_id"]
+      "required": [
+        "string_id"
+      ]
     },
     "localizableText": {
       "description": "Either a raw string or an object containing the string_id of the localized text",
@@ -1217,10 +1272,14 @@
             "properties": {
               "template": {
                 "type": "string",
-                "enum": ["cfr_urlbar_chiclet"]
+                "enum": [
+                  "cfr_urlbar_chiclet"
+                ]
               }
             },
-            "required": ["template"]
+            "required": [
+              "template"
+            ]
           },
           "then": {
             "$ref": "chrome://browser/content/asrouter/schemas/MessagingExperiment.schema.json#/$defs/CFRUrlbarChiclet"
@@ -1232,10 +1291,15 @@
             "properties": {
               "template": {
                 "type": "string",
-                "enum": ["cfr_doorhanger", "milestone_message"]
+                "enum": [
+                  "cfr_doorhanger",
+                  "milestone_message"
+                ]
               }
             },
-            "required": ["template"]
+            "required": [
+              "template"
+            ]
           },
           "then": {
             "$ref": "chrome://browser/content/asrouter/schemas/MessagingExperiment.schema.json#/$defs/ExtensionDoorhanger"
@@ -1247,10 +1311,14 @@
             "properties": {
               "template": {
                 "type": "string",
-                "enum": ["infobar"]
+                "enum": [
+                  "infobar"
+                ]
               }
             },
-            "required": ["template"]
+            "required": [
+              "template"
+            ]
           },
           "then": {
             "$ref": "chrome://browser/content/asrouter/schemas/MessagingExperiment.schema.json#/$defs/InfoBar"
@@ -1262,10 +1330,14 @@
             "properties": {
               "template": {
                 "type": "string",
-                "enum": ["pb_newtab"]
+                "enum": [
+                  "pb_newtab"
+                ]
               }
             },
-            "required": ["template"]
+            "required": [
+              "template"
+            ]
           },
           "then": {
             "$ref": "chrome://browser/content/asrouter/schemas/MessagingExperiment.schema.json#/$defs/NewtabPromoMessage"
@@ -1277,10 +1349,15 @@
             "properties": {
               "template": {
                 "type": "string",
-                "enum": ["spotlight", "feature_callout"]
+                "enum": [
+                  "spotlight",
+                  "feature_callout"
+                ]
               }
             },
-            "required": ["template"]
+            "required": [
+              "template"
+            ]
           },
           "then": {
             "$ref": "chrome://browser/content/asrouter/schemas/MessagingExperiment.schema.json#/$defs/Spotlight"
@@ -1292,10 +1369,14 @@
             "properties": {
               "template": {
                 "type": "string",
-                "enum": ["toast_notification"]
+                "enum": [
+                  "toast_notification"
+                ]
               }
             },
-            "required": ["template"]
+            "required": [
+              "template"
+            ]
           },
           "then": {
             "$ref": "chrome://browser/content/asrouter/schemas/MessagingExperiment.schema.json#/$defs/ToastNotification"
@@ -1307,10 +1388,14 @@
             "properties": {
               "template": {
                 "type": "string",
-                "enum": ["toolbar_badge"]
+                "enum": [
+                  "toolbar_badge"
+                ]
               }
             },
-            "required": ["template"]
+            "required": [
+              "template"
+            ]
           },
           "then": {
             "$ref": "chrome://browser/content/asrouter/schemas/MessagingExperiment.schema.json#/$defs/ToolbarBadgeMessage"
@@ -1322,29 +1407,18 @@
             "properties": {
               "template": {
                 "type": "string",
-                "enum": ["update_action"]
+                "enum": [
+                  "update_action"
+                ]
               }
             },
-            "required": ["template"]
+            "required": [
+              "template"
+            ]
           },
           "then": {
             "$ref": "chrome://browser/content/asrouter/schemas/MessagingExperiment.schema.json#/$defs/UpdateAction"
           }
-        },
-        {
-          "if": {
-            "type": "object",
-            "properties": {
-              "template": {
-                "type": "string",
-                "enum": ["whatsnew_panel_message"]
-              }
-            },
-            "required": ["template"]
-          },
-          "then": {
-            "$ref": "chrome://browser/content/asrouter/schemas/MessagingExperiment.schema.json#/$defs/WhatsNewMessage"
-          }
         }
       ]
     },
@@ -1364,7 +1438,10 @@
           }
         }
       },
-      "required": ["template", "messages"]
+      "required": [
+        "template",
+        "messages"
+      ]
     }
   }
 }
diff --git a/browser/components/asrouter/content-src/schemas/make-schemas.py b/browser/components/asrouter/content-src/schemas/make-schemas.py
index f66490f23a..1f677cab28 100755
--- a/browser/components/asrouter/content-src/schemas/make-schemas.py
+++ b/browser/components/asrouter/content-src/schemas/make-schemas.py
@@ -83,9 +83,6 @@ SCHEMAS = [
             "UpdateAction": (
                 SCHEMA_DIR / "OnboardingMessage" / "UpdateAction.schema.json"
             ),
-            "WhatsNewMessage": (
-                SCHEMA_DIR / "OnboardingMessage" / "WhatsNewMessage.schema.json"
-            ),
         },
         bundle_common=True,
         test_corpus={
diff --git a/browser/components/asrouter/content-src/templates/OnboardingMessage/WhatsNewMessage.schema.json b/browser/components/asrouter/content-src/templates/OnboardingMessage/WhatsNewMessage.schema.json
deleted file mode 100644
index 26e795d068..0000000000
--- a/browser/components/asrouter/content-src/templates/OnboardingMessage/WhatsNewMessage.schema.json
+++ /dev/null
@@ -1,73 +0,0 @@
-{
-  "$schema": "https://json-schema.org/draft/2019-09/schema",
-  "$id": "file:///WhatsNewMessage.schema.json",
-  "title": "WhatsNewMessage",
-  "description": "A template for the messages that appear in the What's New panel.",
-  "allOf": [{ "$ref": "file:///FxMSCommon.schema.json#/$defs/Message" }],
-  "type": "object",
-  "properties": {
-    "content": {
-      "type": "object",
-      "properties": {
-        "layout": {
-          "description": "Different message layouts",
-          "enum": ["tracking-protections"]
-        },
-        "bucket_id": {
-          "type": "string",
-          "description": "A bucket identifier for the addon. This is used in order to anonymize telemetry for history-sensitive targeting."
-        },
-        "published_date": {
-          "type": "integer",
-          "description": "The date/time (number of milliseconds elapsed since January 1, 1970 00:00:00 UTC) the message was published."
-        },
-        "title": {
-          "$ref": "file:///FxMSCommon.schema.json#/$defs/localizableText",
-          "description": "Id of localized string or message override of What's New message title"
-        },
-        "subtitle": {
-          "$ref": "file:///FxMSCommon.schema.json#/$defs/localizableText",
-          "description": "Id of localized string or message override of What's New message subtitle"
-        },
-        "body": {
-          "$ref": "file:///FxMSCommon.schema.json#/$defs/localizableText",
-          "description": "Id of localized string or message override of What's New message body"
-        },
-        "link_text": {
-          "$ref": "file:///FxMSCommon.schema.json#/$defs/localizableText",
-          "description": "(optional) Id of localized string or message override of What's New message link text"
-        },
-        "cta_url": {
-          "description": "Target URL for the What's New message.",
-          "type": "string",
-          "format": "moz-url-format"
-        },
-        "cta_type": {
-          "description": "Type of url open action",
-          "enum": ["OPEN_URL", "OPEN_ABOUT_PAGE", "OPEN_PROTECTION_REPORT"]
-        },
-        "cta_where": {
-          "description": "How to open the cta: new window, tab, focused, unfocused.",
-          "enum": ["current", "tabshifted", "tab", "save", "window"]
-        },
-        "icon_url": {
-          "description": "(optional) URL for the What's New message icon.",
-          "type": "string",
-          "format": "uri"
-        },
-        "icon_alt": {
-          "$ref": "file:///FxMSCommon.schema.json#/$defs/localizableText",
-          "description": "Alt text for image."
-        }
-      },
-      "additionalProperties": true,
-      "required": ["published_date", "title", "body", "cta_url", "bucket_id"]
-    },
-    "template": {
-      "type": "string",
-      "const": "whatsnew_panel_message"
-    }
-  },
-  "required": ["order"],
-  "additionalProperties": true
-}
diff --git a/browser/components/asrouter/content/asrouter-admin.bundle.js b/browser/components/asrouter/content/asrouter-admin.bundle.js
index b38d551a17..e5a1e6dd6a 100644
--- a/browser/components/asrouter/content/asrouter-admin.bundle.js
+++ b/browser/components/asrouter/content/asrouter-admin.bundle.js
@@ -16,15 +16,13 @@ __webpack_require__.r(__webpack_exports__);
 /* harmony export */ __webpack_require__.d(__webpack_exports__, {
 /* harmony export */   ASRouterUtils: () => (/* binding */ ASRouterUtils)
 /* harmony export */ });
-/* harmony import */ var _modules_ActorConstants_sys_mjs__WEBPACK_IMPORTED_MODULE_0__ = __webpack_require__(2);
-/* harmony import */ var _newtab_common_Actions_sys_mjs__WEBPACK_IMPORTED_MODULE_1__ = __webpack_require__(3);
+/* harmony import */ var _modules_ActorConstants_mjs__WEBPACK_IMPORTED_MODULE_0__ = __webpack_require__(2);
+/* harmony import */ var _newtab_common_Actions_mjs__WEBPACK_IMPORTED_MODULE_1__ = __webpack_require__(3);
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-// eslint-disable-next-line mozilla/reject-import-system-module-from-non-system
 
-// eslint-disable-next-line mozilla/reject-import-system-module-from-non-system
 
 
 const ASRouterUtils = {
@@ -46,54 +44,54 @@ const ASRouterUtils = {
   },
   blockById(id, options) {
     return ASRouterUtils.sendMessage({
-      type: _modules_ActorConstants_sys_mjs__WEBPACK_IMPORTED_MODULE_0__.MESSAGE_TYPE_HASH.BLOCK_MESSAGE_BY_ID,
+      type: _modules_ActorConstants_mjs__WEBPACK_IMPORTED_MODULE_0__.MESSAGE_TYPE_HASH.BLOCK_MESSAGE_BY_ID,
       data: { id, ...options },
     });
   },
   modifyMessageJson(content) {
     return ASRouterUtils.sendMessage({
-      type: _modules_ActorConstants_sys_mjs__WEBPACK_IMPORTED_MODULE_0__.MESSAGE_TYPE_HASH.MODIFY_MESSAGE_JSON,
+      type: _modules_ActorConstants_mjs__WEBPACK_IMPORTED_MODULE_0__.MESSAGE_TYPE_HASH.MODIFY_MESSAGE_JSON,
       data: { content },
     });
   },
   executeAction(button_action) {
     return ASRouterUtils.sendMessage({
-      type: _modules_ActorConstants_sys_mjs__WEBPACK_IMPORTED_MODULE_0__.MESSAGE_TYPE_HASH.USER_ACTION,
+      type: _modules_ActorConstants_mjs__WEBPACK_IMPORTED_MODULE_0__.MESSAGE_TYPE_HASH.USER_ACTION,
       data: button_action,
     });
   },
   unblockById(id) {
     return ASRouterUtils.sendMessage({
-      type: _modules_ActorConstants_sys_mjs__WEBPACK_IMPORTED_MODULE_0__.MESSAGE_TYPE_HASH.UNBLOCK_MESSAGE_BY_ID,
+      type: _modules_ActorConstants_mjs__WEBPACK_IMPORTED_MODULE_0__.MESSAGE_TYPE_HASH.UNBLOCK_MESSAGE_BY_ID,
       data: { id },
     });
   },
   blockBundle(bundle) {
     return ASRouterUtils.sendMessage({
-      type: _modules_ActorConstants_sys_mjs__WEBPACK_IMPORTED_MODULE_0__.MESSAGE_TYPE_HASH.BLOCK_BUNDLE,
+      type: _modules_ActorConstants_mjs__WEBPACK_IMPORTED_MODULE_0__.MESSAGE_TYPE_HASH.BLOCK_BUNDLE,
       data: { bundle },
     });
   },
   unblockBundle(bundle) {
     return ASRouterUtils.sendMessage({
-      type: _modules_ActorConstants_sys_mjs__WEBPACK_IMPORTED_MODULE_0__.MESSAGE_TYPE_HASH.UNBLOCK_BUNDLE,
+      type: _modules_ActorConstants_mjs__WEBPACK_IMPORTED_MODULE_0__.MESSAGE_TYPE_HASH.UNBLOCK_BUNDLE,
       data: { bundle },
     });
   },
   overrideMessage(id) {
     return ASRouterUtils.sendMessage({
-      type: _modules_ActorConstants_sys_mjs__WEBPACK_IMPORTED_MODULE_0__.MESSAGE_TYPE_HASH.OVERRIDE_MESSAGE,
+      type: _modules_ActorConstants_mjs__WEBPACK_IMPORTED_MODULE_0__.MESSAGE_TYPE_HASH.OVERRIDE_MESSAGE,
       data: { id },
     });
   },
   editState(key, value) {
     return ASRouterUtils.sendMessage({
-      type: _modules_ActorConstants_sys_mjs__WEBPACK_IMPORTED_MODULE_0__.MESSAGE_TYPE_HASH.EDIT_STATE,
+      type: _modules_ActorConstants_mjs__WEBPACK_IMPORTED_MODULE_0__.MESSAGE_TYPE_HASH.EDIT_STATE,
       data: { [key]: value },
     });
   },
   sendTelemetry(ping) {
-    return ASRouterUtils.sendMessage(_newtab_common_Actions_sys_mjs__WEBPACK_IMPORTED_MODULE_1__.actionCreators.ASRouterUserEvent(ping));
+    return ASRouterUtils.sendMessage(_newtab_common_Actions_mjs__WEBPACK_IMPORTED_MODULE_1__.actionCreators.ASRouterUserEvent(ping));
   },
   getPreviewEndpoint() {
     return null;
@@ -124,7 +122,6 @@ const MESSAGE_TYPE_LIST = [
   "PBNEWTAB_MESSAGE_REQUEST",
   "DOORHANGER_TELEMETRY",
   "TOOLBAR_BADGE_TELEMETRY",
-  "TOOLBAR_PANEL_TELEMETRY",
   "MOMENTS_PAGE_TELEMETRY",
   "INFOBAR_TELEMETRY",
   "SPOTLIGHT_TELEMETRY",
@@ -142,9 +139,7 @@ const MESSAGE_TYPE_LIST = [
   "EVALUATE_JEXL_EXPRESSION",
   "EXPIRE_QUERY_CACHE",
   "FORCE_ATTRIBUTION",
-  "FORCE_WHATSNEW_PANEL",
   "FORCE_PRIVATE_BROWSING_WINDOW",
-  "CLOSE_WHATSNEW_PANEL",
   "OVERRIDE_MESSAGE",
   "MODIFY_MESSAGE_JSON",
   "RESET_PROVIDER_PREF",
@@ -181,6 +176,8 @@ __webpack_require__.r(__webpack_exports__);
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+// This file is accessed from both content and system scopes.
+
 const MAIN_MESSAGE_TYPE = "ActivityStream:Main";
 const CONTENT_MESSAGE_TYPE = "ActivityStream:Content";
 const PRELOAD_MESSAGE_TYPE = "ActivityStream:PreloadedBrowser";
@@ -337,6 +334,7 @@ for (const type of [
   "UPDATE_PINNED_SEARCH_SHORTCUTS",
   "UPDATE_SEARCH_SHORTCUTS",
   "UPDATE_SECTION_PREFS",
+  "WALLPAPERS_SET",
   "WEBEXT_CLICK",
   "WEBEXT_DISMISS",
 ]) {
@@ -550,8 +548,11 @@ function DiscoveryStreamLoadedContent(
   return importContext === UI_CODE ? AlsoToMain(action) : action;
 }
 
-function SetPref(name, value, importContext = globalImportContext) {
-  const action = { type: actionTypes.SET_PREF, data: { name, value } };
+function SetPref(prefName, value, importContext = globalImportContext) {
+  const action = {
+    type: actionTypes.SET_PREF,
+    data: { name: prefName, value },
+  };
   return importContext === UI_CODE ? AlsoToMain(action) : action;
 }
 
@@ -961,7 +962,8 @@ __webpack_require__.r(__webpack_exports__);
 /* harmony export */   ToggleMessageJSON: () => (/* binding */ ToggleMessageJSON),
 /* harmony export */   TogglePrefCheckbox: () => (/* binding */ TogglePrefCheckbox),
 /* harmony export */   ToggleStoryButton: () => (/* binding */ ToggleStoryButton),
-/* harmony export */   renderASRouterAdmin: () => (/* binding */ renderASRouterAdmin)
+/* harmony export */   renderASRouterAdmin: () => (/* binding */ renderASRouterAdmin),
+/* harmony export */   toBinary: () => (/* binding */ toBinary)
 /* harmony export */ });
 /* harmony import */ var _asrouter_utils__WEBPACK_IMPORTED_MODULE_0__ = __webpack_require__(1);
 /* harmony import */ var react__WEBPACK_IMPORTED_MODULE_1__ = __webpack_require__(4);
@@ -985,6 +987,16 @@ function _extends() { _extends = Object.assign ? Object.assign.bind() : function
 const Row = props => /*#__PURE__*/react__WEBPACK_IMPORTED_MODULE_1___default().createElement("tr", _extends({
   className: "message-item"
 }, props), props.children);
+
+// Convert a UTF-8 string to a string in which only one byte of each
+// 16-bit unit is occupied. This is necessary to comply with `btoa` API constraints.
+function toBinary(string) {
+  const codeUnits = new Uint16Array(string.length);
+  for (let i = 0; i < codeUnits.length; i++) {
+    codeUnits[i] = string.charCodeAt(i);
+  }
+  return btoa(String.fromCharCode(...Array.from(new Uint8Array(codeUnits.buffer))));
+}
 function relativeTime(timestamp) {
   if (!timestamp) {
     return "";
@@ -1427,7 +1439,7 @@ class ASRouterAdminInner extends (react__WEBPACK_IMPORTED_MODULE_1___default().P
       className: "button modify",
       onClick: () => this.modifyJson(msg)
     }, "Modify"), aboutMessagePreviewSupported ? /*#__PURE__*/react__WEBPACK_IMPORTED_MODULE_1___default().createElement(_CopyButton__WEBPACK_IMPORTED_MODULE_4__.CopyButton, {
-      transformer: text => `about:messagepreview?json=${encodeURIComponent(btoa(text))}`,
+      transformer: text => `about:messagepreview?json=${encodeURIComponent(toBinary(text))}`,
       label: "Share",
       copiedLabel: "Copied!",
       inputSelector: `#${msg.id}-textarea`,
diff --git a/browser/components/asrouter/docs/targeting-attributes.md b/browser/components/asrouter/docs/targeting-attributes.md
index 89c5a6b6c6..b0049a4f1b 100644
--- a/browser/components/asrouter/docs/targeting-attributes.md
+++ b/browser/components/asrouter/docs/targeting-attributes.md
@@ -44,7 +44,6 @@ Please note that some targeting attributes require stricter controls on the tele
 * [isFxASignedIn](#isFxASignedIn)
 * [isMajorUpgrade](#ismajorupgrade)
 * [isRTAMO](#isrtamo)
-* [isWhatsNewPanelEnabled](#iswhatsnewpanelenabled)
 * [launchOnLoginEnabled](#launchonloginenabled)
 * [locale](#locale)
 * [localeLanguageCode](#localelanguagecode)
@@ -630,16 +629,6 @@ Boolean pref that gets set the first time the user opens the FxA toolbar panel
 declare const hasAccessedFxAPanel: boolean;
 ```
 
-### `isWhatsNewPanelEnabled`
-
-Boolean pref that controls if the What's New panel feature is enabled
-
-#### Definition
-
-```ts
-declare const isWhatsNewPanelEnabled: boolean;
-```
-
 ### `totalBlockedCount`
 
 Total number of events from the content blocking database
diff --git a/browser/components/asrouter/modules/ASRouter.sys.mjs b/browser/components/asrouter/modules/ASRouter.sys.mjs
index e46c57f685..b36a9023e1 100644
--- a/browser/components/asrouter/modules/ASRouter.sys.mjs
+++ b/browser/components/asrouter/modules/ASRouter.sys.mjs
@@ -55,7 +55,6 @@ ChromeUtils.defineESModuleGetters(lazy, {
   Spotlight: "resource:///modules/asrouter/Spotlight.sys.mjs",
   ToastNotification: "resource:///modules/asrouter/ToastNotification.sys.mjs",
   ToolbarBadgeHub: "resource:///modules/asrouter/ToolbarBadgeHub.sys.mjs",
-  ToolbarPanelHub: "resource:///modules/asrouter/ToolbarPanelHub.sys.mjs",
 });
 
 XPCOMUtils.defineLazyServiceGetters(lazy, {
@@ -67,7 +66,7 @@ ChromeUtils.defineLazyGetter(lazy, "log", () => {
   );
   return new Logger("ASRouter");
 });
-import { actionCreators as ac } from "resource://activity-stream/common/Actions.sys.mjs";
+import { actionCreators as ac } from "resource://activity-stream/common/Actions.mjs";
 import { MESSAGING_EXPERIMENTS_DEFAULT_FEATURES } from "resource:///modules/asrouter/MessagingExperimentConstants.sys.mjs";
 import { CFRMessageProvider } from "resource:///modules/asrouter/CFRMessageProvider.sys.mjs";
 import { OnboardingMessageProvider } from "resource:///modules/asrouter/OnboardingMessageProvider.sys.mjs";
@@ -620,7 +619,6 @@ export class _ASRouter {
     this._onLocaleChanged = this._onLocaleChanged.bind(this);
     this.isUnblockedMessage = this.isUnblockedMessage.bind(this);
     this.unblockAll = this.unblockAll.bind(this);
-    this.forceWNPanel = this.forceWNPanel.bind(this);
     this._onExperimentEnrollmentsUpdated =
       this._onExperimentEnrollmentsUpdated.bind(this);
     this.forcePBWindow = this.forcePBWindow.bind(this);
@@ -995,10 +993,6 @@ export class _ASRouter {
       unblockMessageById: this.unblockMessageById,
       sendTelemetry: this.sendTelemetry,
     });
-    lazy.ToolbarPanelHub.init(this.waitForInitialized, {
-      getMessages: this.handleMessageRequest,
-      sendTelemetry: this.sendTelemetry,
-    });
     lazy.MomentsPageHub.init(this.waitForInitialized, {
       handleMessageRequest: this.handleMessageRequest,
       addImpression: this.addImpression,
@@ -1055,7 +1049,6 @@ export class _ASRouter {
 
     lazy.ASRouterPreferences.removeListener(this.onPrefChange);
     lazy.ASRouterPreferences.uninit();
-    lazy.ToolbarPanelHub.uninit();
     lazy.ToolbarBadgeHub.uninit();
     lazy.MomentsPageHub.uninit();
 
@@ -1309,16 +1302,6 @@ export class _ASRouter {
     return true;
   }
 
-  async _extraTemplateStrings(originalMessage) {
-    let extraTemplateStrings;
-    let localProvider = this._findProvider(originalMessage.provider);
-    if (localProvider && localProvider.getExtraAttributes) {
-      extraTemplateStrings = await localProvider.getExtraAttributes();
-    }
-
-    return extraTemplateStrings;
-  }
-
   _findProvider(providerID) {
     return this._localProviders[
       this.state.providers.find(i => i.id === providerID).localProvider
@@ -1346,11 +1329,6 @@ export class _ASRouter {
     }
 
     switch (message.template) {
-      case "whatsnew_panel_message":
-        if (force) {
-          lazy.ToolbarPanelHub.forceShowMessage(browser, message);
-        }
-        break;
       case "cfr_doorhanger":
       case "milestone_message":
         if (force) {
@@ -2005,29 +1983,6 @@ export class _ASRouter {
     );
   }
 
-  async forceWNPanel(browser) {
-    let win = browser.ownerGlobal;
-    await lazy.ToolbarPanelHub.enableToolbarButton();
-
-    win.PanelUI.showSubView(
-      "PanelUI-whatsNew",
-      win.document.getElementById("whats-new-menu-button")
-    );
-
-    let panel = win.document.getElementById("customizationui-widget-panel");
-    // Set the attribute to keep the panel open
-    panel.setAttribute("noautohide", true);
-  }
-
-  async closeWNPanel(browser) {
-    let win = browser.ownerGlobal;
-    let panel = win.document.getElementById("customizationui-widget-panel");
-    // Set the attribute to allow the panel to close
-    panel.setAttribute("noautohide", false);
-    // Removing the button is enough to close the panel.
-    await lazy.ToolbarPanelHub._hideToolbarButton(win);
-  }
-
   async _onExperimentEnrollmentsUpdated() {
     const experimentProvider = this.state.providers.find(
       p => p.id === "messaging-experiments"
diff --git a/browser/components/asrouter/modules/ASRouterParentProcessMessageHandler.sys.mjs b/browser/components/asrouter/modules/ASRouterParentProcessMessageHandler.sys.mjs
index c2f5fcd884..8aa4d7dbc9 100644
--- a/browser/components/asrouter/modules/ASRouterParentProcessMessageHandler.sys.mjs
+++ b/browser/components/asrouter/modules/ASRouterParentProcessMessageHandler.sys.mjs
@@ -4,7 +4,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 import { ASRouterPreferences } from "resource:///modules/asrouter/ASRouterPreferences.sys.mjs";
-import { MESSAGE_TYPE_HASH as msg } from "resource:///modules/asrouter/ActorConstants.sys.mjs";
+import { MESSAGE_TYPE_HASH as msg } from "resource:///modules/asrouter/ActorConstants.mjs";
 
 export class ASRouterParentProcessMessageHandler {
   constructor({
@@ -27,7 +27,6 @@ export class ASRouterParentProcessMessageHandler {
     switch (type) {
       case msg.INFOBAR_TELEMETRY:
       case msg.TOOLBAR_BADGE_TELEMETRY:
-      case msg.TOOLBAR_PANEL_TELEMETRY:
       case msg.MOMENTS_PAGE_TELEMETRY:
       case msg.DOORHANGER_TELEMETRY:
       case msg.SPOTLIGHT_TELEMETRY:
@@ -128,12 +127,6 @@ export class ASRouterParentProcessMessageHandler {
       case msg.FORCE_PRIVATE_BROWSING_WINDOW: {
         return this._router.forcePBWindow(browser, data.message);
       }
-      case msg.FORCE_WHATSNEW_PANEL: {
-        return this._router.forceWNPanel(browser);
-      }
-      case msg.CLOSE_WHATSNEW_PANEL: {
-        return this._router.closeWNPanel(browser);
-      }
       case msg.MODIFY_MESSAGE_JSON: {
         return this._router.routeCFRMessage(data.content, browser, data, true);
       }
diff --git a/browser/components/asrouter/modules/ASRouterTargeting.sys.mjs b/browser/components/asrouter/modules/ASRouterTargeting.sys.mjs
index d76b303fc6..9773eda270 100644
--- a/browser/components/asrouter/modules/ASRouterTargeting.sys.mjs
+++ b/browser/components/asrouter/modules/ASRouterTargeting.sys.mjs
@@ -74,12 +74,6 @@ XPCOMUtils.defineLazyPreferenceGetter(
 );
 XPCOMUtils.defineLazyPreferenceGetter(
   lazy,
-  "isWhatsNewPanelEnabled",
-  "browser.messaging-system.whatsNewPanel.enabled",
-  false
-);
-XPCOMUtils.defineLazyPreferenceGetter(
-  lazy,
   "hasAccessedFxAPanel",
   "identity.fxaccounts.toolbar.accessed",
   false
@@ -704,9 +698,6 @@ const TargetingGetters = {
   get hasAccessedFxAPanel() {
     return lazy.hasAccessedFxAPanel;
   },
-  get isWhatsNewPanelEnabled() {
-    return lazy.isWhatsNewPanelEnabled;
-  },
   get userPrefs() {
     return {
       cfrFeatures: lazy.cfrFeaturesUserPref,
diff --git a/browser/components/asrouter/modules/ActorConstants.sys.mjs b/browser/components/asrouter/modules/ActorConstants.mjs
index 4c996552ab..c1c18e006e 100644
--- a/browser/components/asrouter/modules/ActorConstants.sys.mjs
+++ b/browser/components/asrouter/modules/ActorConstants.mjs
@@ -12,7 +12,6 @@ export const MESSAGE_TYPE_LIST = [
   "PBNEWTAB_MESSAGE_REQUEST",
   "DOORHANGER_TELEMETRY",
   "TOOLBAR_BADGE_TELEMETRY",
-  "TOOLBAR_PANEL_TELEMETRY",
   "MOMENTS_PAGE_TELEMETRY",
   "INFOBAR_TELEMETRY",
   "SPOTLIGHT_TELEMETRY",
@@ -30,9 +29,7 @@ export const MESSAGE_TYPE_LIST = [
   "EVALUATE_JEXL_EXPRESSION",
   "EXPIRE_QUERY_CACHE",
   "FORCE_ATTRIBUTION",
-  "FORCE_WHATSNEW_PANEL",
   "FORCE_PRIVATE_BROWSING_WINDOW",
-  "CLOSE_WHATSNEW_PANEL",
   "OVERRIDE_MESSAGE",
   "MODIFY_MESSAGE_JSON",
   "RESET_PROVIDER_PREF",
diff --git a/browser/components/asrouter/modules/MomentsPageHub.sys.mjs b/browser/components/asrouter/modules/MomentsPageHub.sys.mjs
index 84fee3b517..3a59e9d450 100644
--- a/browser/components/asrouter/modules/MomentsPageHub.sys.mjs
+++ b/browser/components/asrouter/modules/MomentsPageHub.sys.mjs
@@ -165,7 +165,7 @@ export class _MomentsPageHub {
 }
 
 /**
- * ToolbarBadgeHub - singleton instance of _ToolbarBadgeHub that can initiate
+ * MomentsPageHub - singleton instance of _MomentsPageHub that can initiate
  * message requests and render messages.
  */
 export const MomentsPageHub = new _MomentsPageHub();
diff --git a/browser/components/asrouter/modules/OnboardingMessageProvider.sys.mjs b/browser/components/asrouter/modules/OnboardingMessageProvider.sys.mjs
index ceded6b755..3cfbbb3f34 100644
--- a/browser/components/asrouter/modules/OnboardingMessageProvider.sys.mjs
+++ b/browser/components/asrouter/modules/OnboardingMessageProvider.sys.mjs
@@ -1210,6 +1210,106 @@ const BASE_MESSAGES = () => [
       id: "defaultBrowserCheck",
     },
   },
+  {
+    id: "SET_DEFAULT_BROWSER_GUIDANCE_NOTIFICATION_WIN10",
+    template: "toast_notification",
+    content: {
+      title: {
+        string_id: "default-browser-guidance-notification-title",
+      },
+      body: {
+        string_id:
+          "default-browser-guidance-notification-body-instruction-win10",
+      },
+      launch_action: {
+        type: "OPEN_URL",
+        data: {
+          args: "https://support.mozilla.org/1/firefox/%VERSION%/%OS%/%LOCALE%/win-set-firefox-default-browser",
+          where: "tabshifted",
+        },
+      },
+      requireInteraction: true,
+      actions: [
+        {
+          action: "info-page",
+          title: {
+            string_id: "default-browser-guidance-notification-info-page",
+          },
+          launch_action: {
+            type: "OPEN_URL",
+            data: {
+              args: "https://support.mozilla.org/1/firefox/%VERSION%/%OS%/%LOCALE%/win-set-firefox-default-browser",
+              where: "tabshifted",
+            },
+          },
+        },
+        {
+          action: "dismiss",
+          title: {
+            string_id: "default-browser-guidance-notification-dismiss",
+          },
+          windowsSystemActivationType: true,
+        },
+      ],
+      tag: "set-default-guidance-notification",
+    },
+    // Both Windows 10 and 11 return `os.windowsVersion == 10.0`. We limit to
+    // only Windows 10 with `os.windowsBuildNumber < 22000`. We need this due to
+    // Windows 10 and 11 having substantively different UX for Windows Settings.
+    targeting:
+      "os.isWindows && os.windowsVersion >= 10.0 && os.windowsBuildNumber < 22000",
+    trigger: { id: "deeplinkedToWindowsSettingsUI" },
+  },
+  {
+    id: "SET_DEFAULT_BROWSER_GUIDANCE_NOTIFICATION_WIN11",
+    template: "toast_notification",
+    content: {
+      title: {
+        string_id: "default-browser-guidance-notification-title",
+      },
+      body: {
+        string_id:
+          "default-browser-guidance-notification-body-instruction-win11",
+      },
+      launch_action: {
+        type: "OPEN_URL",
+        data: {
+          args: "https://support.mozilla.org/1/firefox/%VERSION%/%OS%/%LOCALE%/win-set-firefox-default-browser",
+          where: "tabshifted",
+        },
+      },
+      requireInteraction: true,
+      actions: [
+        {
+          action: "info-page",
+          title: {
+            string_id: "default-browser-guidance-notification-info-page",
+          },
+          launch_action: {
+            type: "OPEN_URL",
+            data: {
+              args: "https://support.mozilla.org/1/firefox/%VERSION%/%OS%/%LOCALE%/win-set-firefox-default-browser",
+              where: "tabshifted",
+            },
+          },
+        },
+        {
+          action: "dismiss",
+          title: {
+            string_id: "default-browser-guidance-notification-dismiss",
+          },
+          windowsSystemActivationType: true,
+        },
+      ],
+      tag: "set-default-guidance-notification",
+    },
+    // Both Windows 10 and 11 return `os.windowsVersion == 10.0`. We limit to
+    // only Windows 11 with `os.windowsBuildNumber >= 22000`. We need this due to
+    // Windows 10 and 11 having substantively different UX for Windows Settings.
+    targeting:
+      "os.isWindows && os.windowsVersion >= 10.0 && os.windowsBuildNumber >= 22000",
+    trigger: { id: "deeplinkedToWindowsSettingsUI" },
+  },
 ];
 
 // Eventually, move Feature Callout messages to their own provider
diff --git a/browser/components/asrouter/modules/PanelTestProvider.sys.mjs b/browser/components/asrouter/modules/PanelTestProvider.sys.mjs
index 7a7ff1e1fc..5180e2e6a2 100644
--- a/browser/components/asrouter/modules/PanelTestProvider.sys.mjs
+++ b/browser/components/asrouter/modules/PanelTestProvider.sys.mjs
@@ -20,134 +20,6 @@ const MESSAGES = () => [
     trigger: { id: "momentsUpdate" },
   },
   {
-    id: "WHATS_NEW_FINGERPRINTER_COUNTER_ALT",
-    template: "whatsnew_panel_message",
-    order: 6,
-    content: {
-      bucket_id: "WHATS_NEW_72",
-      published_date: 1574776601000,
-      title: "Title",
-      icon_url:
-        "chrome://activity-stream/content/data/content/assets/protection-report-icon.png",
-      icon_alt: { string_id: "cfr-badge-reader-label-newfeature" },
-      body: "Message body",
-      link_text: "Click here",
-      cta_url: "about:blank",
-      cta_type: "OPEN_PROTECTION_REPORT",
-    },
-    targeting: `firefoxVersion >= 72`,
-    trigger: { id: "whatsNewPanelOpened" },
-  },
-  {
-    id: "WHATS_NEW_70_1",
-    template: "whatsnew_panel_message",
-    order: 3,
-    content: {
-      bucket_id: "WHATS_NEW_70_1",
-      published_date: 1560969794394,
-      title: "Protection Is Our Focus",
-      icon_url:
-        "chrome://activity-stream/content/data/content/assets/whatsnew-send-icon.png",
-      icon_alt: "Firefox Send Logo",
-      body: "The New Enhanced Tracking Protection, gives you the best level of protection and performance. Discover how this version is the safest version of firefox ever made.",
-      cta_url: "https://blog.mozilla.org/",
-      cta_type: "OPEN_URL",
-    },
-    targeting: `firefoxVersion > 69`,
-    trigger: { id: "whatsNewPanelOpened" },
-  },
-  {
-    id: "WHATS_NEW_70_2",
-    template: "whatsnew_panel_message",
-    order: 1,
-    content: {
-      bucket_id: "WHATS_NEW_70_1",
-      published_date: 1560969794394,
-      title: "Another thing new in Firefox 70",
-      body: "The New Enhanced Tracking Protection, gives you the best level of protection and performance. Discover how this version is the safest version of firefox ever made.",
-      link_text: "Learn more on our blog",
-      cta_url: "https://blog.mozilla.org/",
-      cta_type: "OPEN_URL",
-    },
-    targeting: `firefoxVersion > 69`,
-    trigger: { id: "whatsNewPanelOpened" },
-  },
-  {
-    id: "WHATS_NEW_SEARCH_SHORTCUTS_84",
-    template: "whatsnew_panel_message",
-    order: 2,
-    content: {
-      bucket_id: "WHATS_NEW_SEARCH_SHORTCUTS_84",
-      published_date: 1560969794394,
-      title: "Title",
-      icon_url: "chrome://global/skin/icons/check.svg",
-      icon_alt: "",
-      body: "Message content",
-      cta_url:
-        "https://support.mozilla.org/1/firefox/%VERSION%/%OS%/%LOCALE%/search-shortcuts",
-      cta_type: "OPEN_URL",
-      link_text: "Click here",
-    },
-    targeting: "firefoxVersion >= 84",
-    trigger: {
-      id: "whatsNewPanelOpened",
-    },
-  },
-  {
-    id: "WHATS_NEW_PIONEER_82",
-    template: "whatsnew_panel_message",
-    order: 1,
-    content: {
-      bucket_id: "WHATS_NEW_PIONEER_82",
-      published_date: 1603152000000,
-      title: "Put your data to work for a better internet",
-      body: "Contribute your data to Mozilla's Pioneer program to help researchers understand pressing technology issues like misinformation, data privacy, and ethical AI.",
-      cta_url: "about:blank",
-      cta_where: "tab",
-      cta_type: "OPEN_ABOUT_PAGE",
-      link_text: "Join Pioneer",
-    },
-    targeting: "firefoxVersion >= 82",
-    trigger: {
-      id: "whatsNewPanelOpened",
-    },
-  },
-  {
-    id: "WHATS_NEW_MEDIA_SESSION_82",
-    template: "whatsnew_panel_message",
-    order: 3,
-    content: {
-      bucket_id: "WHATS_NEW_MEDIA_SESSION_82",
-      published_date: 1603152000000,
-      title: "Title",
-      body: "Message content",
-      cta_url:
-        "https://support.mozilla.org/1/firefox/%VERSION%/%OS%/%LOCALE%/media-keyboard-control",
-      cta_type: "OPEN_URL",
-      link_text: "Click here",
-    },
-    targeting: "firefoxVersion >= 82",
-    trigger: {
-      id: "whatsNewPanelOpened",
-    },
-  },
-  {
-    id: "WHATS_NEW_69_1",
-    template: "whatsnew_panel_message",
-    order: 1,
-    content: {
-      bucket_id: "WHATS_NEW_69_1",
-      published_date: 1557346235089,
-      title: "Something new in Firefox 69",
-      body: "The New Enhanced Tracking Protection, gives you the best level of protection and performance. Discover how this version is the safest version of firefox ever made.",
-      link_text: "Learn more on our blog",
-      cta_url: "https://blog.mozilla.org/",
-      cta_type: "OPEN_URL",
-    },
-    targeting: `firefoxVersion > 68`,
-    trigger: { id: "whatsNewPanelOpened" },
-  },
-  {
     id: "PERSONALIZED_CFR_MESSAGE",
     template: "cfr_doorhanger",
     groups: ["cfr"],
diff --git a/browser/components/asrouter/modules/ToolbarBadgeHub.sys.mjs b/browser/components/asrouter/modules/ToolbarBadgeHub.sys.mjs
index 57fd104f19..36f7ca5005 100644
--- a/browser/components/asrouter/modules/ToolbarBadgeHub.sys.mjs
+++ b/browser/components/asrouter/modules/ToolbarBadgeHub.sys.mjs
@@ -10,7 +10,6 @@ ChromeUtils.defineESModuleGetters(lazy, {
   clearTimeout: "resource://gre/modules/Timer.sys.mjs",
   requestIdleCallback: "resource://gre/modules/Timer.sys.mjs",
   setTimeout: "resource://gre/modules/Timer.sys.mjs",
-  ToolbarPanelHub: "resource:///modules/asrouter/ToolbarPanelHub.sys.mjs",
 });
 
 let notificationsByWindow = new WeakMap();
@@ -19,9 +18,6 @@ export class _ToolbarBadgeHub {
   constructor() {
     this.id = "toolbar-badge-hub";
     this.state = {};
-    this.prefs = {
-      WHATSNEW_TOOLBAR_PANEL: "browser.messaging-system.whatsNewPanel.enabled",
-    };
     this.removeAllNotifications = this.removeAllNotifications.bind(this);
     this.removeToolbarNotification = this.removeToolbarNotification.bind(this);
     this.addToolbarNotification = this.addToolbarNotification.bind(this);
@@ -62,34 +58,12 @@ export class _ToolbarBadgeHub {
       triggerId: "toolbarBadgeUpdate",
       template: "toolbar_badge",
     });
-    // Listen for pref changes that could trigger new badges
-    Services.prefs.addObserver(this.prefs.WHATSNEW_TOOLBAR_PANEL, this);
-  }
-
-  observe(aSubject, aTopic, aPrefName) {
-    switch (aPrefName) {
-      case this.prefs.WHATSNEW_TOOLBAR_PANEL:
-        this.messageRequest({
-          triggerId: "toolbarBadgeUpdate",
-          template: "toolbar_badge",
-        });
-        break;
-    }
   }
 
   maybeInsertFTL(win) {
     win.MozXULElement.insertFTLIfNeeded("browser/newtab/asrouter.ftl");
   }
 
-  executeAction({ id }) {
-    switch (id) {
-      case "show-whatsnew-button":
-        lazy.ToolbarPanelHub.enableToolbarButton();
-        lazy.ToolbarPanelHub.enableAppmenuButton();
-        break;
-    }
-  }
-
   _clearBadgeTimeout() {
     if (this.state.showBadgeTimeoutId) {
       lazy.clearTimeout(this.state.showBadgeTimeoutId);
@@ -153,9 +127,6 @@ export class _ToolbarBadgeHub {
 
   addToolbarNotification(win, message) {
     const document = win.browser.ownerDocument;
-    if (message.content.action) {
-      this.executeAction({ ...message.content.action, message_id: message.id });
-    }
     let toolbarbutton = document.getElementById(message.content.target);
     if (toolbarbutton) {
       const badge = toolbarbutton.querySelector(".toolbarbutton-badge");
@@ -211,12 +182,6 @@ export class _ToolbarBadgeHub {
   }
 
   registerBadgeToAllWindows(message) {
-    if (message.template === "update_action") {
-      this.executeAction({ ...message.content.action, message_id: message.id });
-      // No badge to set only an action to execute
-      return;
-    }
-
     lazy.EveryWindow.registerCallback(
       this.id,
       win => {
@@ -297,7 +262,6 @@ export class _ToolbarBadgeHub {
     this.state = {};
     this._initialized = false;
     notificationsByWindow = new WeakMap();
-    Services.prefs.removeObserver(this.prefs.WHATSNEW_TOOLBAR_PANEL, this);
   }
 }
 
diff --git a/browser/components/asrouter/modules/ToolbarPanelHub.sys.mjs b/browser/components/asrouter/modules/ToolbarPanelHub.sys.mjs
deleted file mode 100644
index 519bca8a89..0000000000
--- a/browser/components/asrouter/modules/ToolbarPanelHub.sys.mjs
+++ /dev/null
@@ -1,544 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-const lazy = {};
-
-// We use importESModule here instead of static import so that
-// the Karma test environment won't choke on this module. This
-// is because the Karma test environment already stubs out
-// XPCOMUtils. That environment overrides importESModule to be a no-op
-// (which can't be done for a static import statement).
-
-// eslint-disable-next-line mozilla/use-static-import
-const { XPCOMUtils } = ChromeUtils.importESModule(
-  "resource://gre/modules/XPCOMUtils.sys.mjs"
-);
-
-ChromeUtils.defineESModuleGetters(lazy, {
-  EveryWindow: "resource:///modules/EveryWindow.sys.mjs",
-  PanelMultiView: "resource:///modules/PanelMultiView.sys.mjs",
-  PrivateBrowsingUtils: "resource://gre/modules/PrivateBrowsingUtils.sys.mjs",
-  SpecialMessageActions:
-    "resource://messaging-system/lib/SpecialMessageActions.sys.mjs",
-  RemoteL10n: "resource:///modules/asrouter/RemoteL10n.sys.mjs",
-});
-
-XPCOMUtils.defineLazyServiceGetter(
-  lazy,
-  "TrackingDBService",
-  "@mozilla.org/tracking-db-service;1",
-  "nsITrackingDBService"
-);
-
-const idToTextMap = new Map([
-  [Ci.nsITrackingDBService.TRACKERS_ID, "trackerCount"],
-  [Ci.nsITrackingDBService.TRACKING_COOKIES_ID, "cookieCount"],
-  [Ci.nsITrackingDBService.CRYPTOMINERS_ID, "cryptominerCount"],
-  [Ci.nsITrackingDBService.FINGERPRINTERS_ID, "fingerprinterCount"],
-  [Ci.nsITrackingDBService.SOCIAL_ID, "socialCount"],
-]);
-
-const WHATSNEW_ENABLED_PREF = "browser.messaging-system.whatsNewPanel.enabled";
-const PROTECTIONS_PANEL_INFOMSG_PREF =
-  "browser.protections_panel.infoMessage.seen";
-
-const TOOLBAR_BUTTON_ID = "whats-new-menu-button";
-const APPMENU_BUTTON_ID = "appMenu-whatsnew-button";
-
-const BUTTON_STRING_ID = "cfr-whatsnew-button";
-const WHATS_NEW_PANEL_SELECTOR = "PanelUI-whatsNew-message-container";
-
-export class _ToolbarPanelHub {
-  constructor() {
-    this.triggerId = "whatsNewPanelOpened";
-    this._showAppmenuButton = this._showAppmenuButton.bind(this);
-    this._hideAppmenuButton = this._hideAppmenuButton.bind(this);
-    this._showToolbarButton = this._showToolbarButton.bind(this);
-    this._hideToolbarButton = this._hideToolbarButton.bind(this);
-
-    this.state = {};
-    this._initialized = false;
-  }
-
-  async init(waitForInitialized, { getMessages, sendTelemetry }) {
-    if (this._initialized) {
-      return;
-    }
-
-    this._initialized = true;
-    this._getMessages = getMessages;
-    this._sendTelemetry = sendTelemetry;
-    // Wait for ASRouter messages to become available in order to know
-    // if we can show the What's New panel
-    await waitForInitialized;
-    // Enable the application menu button so that the user can access
-    // the panel outside of the toolbar button
-    await this.enableAppmenuButton();
-
-    this.state = {
-      protectionPanelMessageSeen: Services.prefs.getBoolPref(
-        PROTECTIONS_PANEL_INFOMSG_PREF,
-        false
-      ),
-    };
-  }
-
-  uninit() {
-    this._initialized = false;
-    lazy.EveryWindow.unregisterCallback(TOOLBAR_BUTTON_ID);
-    lazy.EveryWindow.unregisterCallback(APPMENU_BUTTON_ID);
-  }
-
-  get messages() {
-    return this._getMessages({
-      template: "whatsnew_panel_message",
-      triggerId: "whatsNewPanelOpened",
-      returnAll: true,
-    });
-  }
-
-  toggleWhatsNewPref(event) {
-    // Checkbox onclick handler gets called before the checkbox state gets toggled,
-    // so we have to call it with the opposite value.
-    let newValue = !event.target.checked;
-    Services.prefs.setBoolPref(WHATSNEW_ENABLED_PREF, newValue);
-
-    this.sendUserEventTelemetry(
-      event.target.ownerGlobal,
-      "WNP_PREF_TOGGLE",
-      // Message id is not applicable in this case, the notification state
-      // is not related to a particular message
-      { id: "n/a" },
-      { value: { prefValue: newValue } }
-    );
-  }
-
-  maybeInsertFTL(win) {
-    win.MozXULElement.insertFTLIfNeeded("browser/newtab/asrouter.ftl");
-    win.MozXULElement.insertFTLIfNeeded("toolkit/branding/brandings.ftl");
-    win.MozXULElement.insertFTLIfNeeded("toolkit/branding/accounts.ftl");
-  }
-
-  maybeLoadCustomElement(win) {
-    if (!win.customElements.get("remote-text")) {
-      Services.scriptloader.loadSubScript(
-        "resource://activity-stream/data/custom-elements/paragraph.js",
-        win
-      );
-    }
-  }
-
-  // Turns on the Appmenu (hamburger menu) button for all open windows and future windows.
-  async enableAppmenuButton() {
-    if ((await this.messages).length) {
-      lazy.EveryWindow.registerCallback(
-        APPMENU_BUTTON_ID,
-        this._showAppmenuButton,
-        this._hideAppmenuButton
-      );
-    }
-  }
-
-  // Removes the button from the Appmenu.
-  // Only used in tests.
-  disableAppmenuButton() {
-    lazy.EveryWindow.unregisterCallback(APPMENU_BUTTON_ID);
-  }
-
-  // Turns on the Toolbar button for all open windows and future windows.
-  async enableToolbarButton() {
-    if ((await this.messages).length) {
-      lazy.EveryWindow.registerCallback(
-        TOOLBAR_BUTTON_ID,
-        this._showToolbarButton,
-        this._hideToolbarButton
-      );
-    }
-  }
-
-  // When the panel is hidden we want to run some cleanup
-  _onPanelHidden(win) {
-    const panelContainer = win.document.getElementById(
-      "customizationui-widget-panel"
-    );
-    // When the panel is hidden we want to remove any toolbar buttons that
-    // might have been added as an entry point to the panel
-    const removeToolbarButton = () => {
-      lazy.EveryWindow.unregisterCallback(TOOLBAR_BUTTON_ID);
-    };
-    if (!panelContainer) {
-      return;
-    }
-    panelContainer.addEventListener("popuphidden", removeToolbarButton, {
-      once: true,
-    });
-  }
-
-  // Newer messages first and use `order` field to decide between messages
-  // with the same timestamp
-  _sortWhatsNewMessages(m1, m2) {
-    // Sort by published_date in descending order.
-    if (m1.content.published_date === m2.content.published_date) {
-      // Ascending order
-      return m1.order - m2.order;
-    }
-    if (m1.content.published_date > m2.content.published_date) {
-      return -1;
-    }
-    return 1;
-  }
-
-  // Render what's new messages into the panel.
-  async renderMessages(win, doc, containerId, options = {}) {
-    // Set the checked status of the footer checkbox
-    let value = Services.prefs.getBoolPref(WHATSNEW_ENABLED_PREF);
-    let checkbox = win.document.getElementById("panelMenu-toggleWhatsNew");
-
-    checkbox.checked = value;
-
-    this.maybeLoadCustomElement(win);
-    const messages =
-      (options.force && options.messages) ||
-      (await this.messages).sort(this._sortWhatsNewMessages);
-    const container = lazy.PanelMultiView.getViewNode(doc, containerId);
-
-    if (messages) {
-      // Targeting attribute state might have changed making new messages
-      // available and old messages invalid, we need to refresh
-      this.removeMessages(win, containerId);
-      let previousDate = 0;
-      // Get and store any variable part of the message content
-      this.state.contentArguments = await this._contentArguments();
-      for (let message of messages) {
-        container.appendChild(
-          this._createMessageElements(win, doc, message, previousDate)
-        );
-        previousDate = message.content.published_date;
-      }
-    }
-
-    this._onPanelHidden(win);
-
-    // Panel impressions are not associated with one particular message
-    // but with a set of messages. We concatenate message ids and send them
-    // back for every impression.
-    const eventId = {
-      id: messages
-        .map(({ id }) => id)
-        .sort()
-        .join(","),
-    };
-    // Check `mainview` attribute to determine if the panel is shown as a
-    // subview (inside the application menu) or as a toolbar dropdown.
-    // https://searchfox.org/mozilla-central/rev/07f7390618692fa4f2a674a96b9b677df3a13450/browser/components/customizableui/PanelMultiView.jsm#1268
-    const mainview = win.PanelUI.whatsNewPanel.hasAttribute("mainview");
-    this.sendUserEventTelemetry(win, "IMPRESSION", eventId, {
-      value: { view: mainview ? "toolbar_dropdown" : "application_menu" },
-    });
-  }
-
-  removeMessages(win, containerId) {
-    const doc = win.document;
-    const messageNodes = lazy.PanelMultiView.getViewNode(
-      doc,
-      containerId
-    ).querySelectorAll(".whatsNew-message");
-    for (const messageNode of messageNodes) {
-      messageNode.remove();
-    }
-  }
-
-  /**
-   * Dispatch the action defined in the message and user telemetry event.
-   */
-  _dispatchUserAction(win, message) {
-    let url;
-    try {
-      // Set platform specific path variables for SUMO articles
-      url = Services.urlFormatter.formatURL(message.content.cta_url);
-    } catch (e) {
-      console.error(e);
-      url = message.content.cta_url;
-    }
-    lazy.SpecialMessageActions.handleAction(
-      {
-        type: message.content.cta_type,
-        data: {
-          args: url,
-          where: message.content.cta_where || "tabshifted",
-        },
-      },
-      win.browser
-    );
-
-    this.sendUserEventTelemetry(win, "CLICK", message);
-  }
-
-  /**
-   * Attach event listener to dispatch message defined action.
-   */
-  _attachCommandListener(win, element, message) {
-    // Add event listener for `mouseup` not to overlap with the
-    // `mousedown` & `click` events dispatched from PanelMultiView.sys.mjs
-    // https://searchfox.org/mozilla-central/rev/7531325c8660cfa61bf71725f83501028178cbb9/browser/components/customizableui/PanelMultiView.jsm#1830-1837
-    element.addEventListener("mouseup", () => {
-      this._dispatchUserAction(win, message);
-    });
-    element.addEventListener("keyup", e => {
-      if (e.key === "Enter" || e.key === " ") {
-        this._dispatchUserAction(win, message);
-      }
-    });
-  }
-
-  _createMessageElements(win, doc, message, previousDate) {
-    const { content } = message;
-    const messageEl = lazy.RemoteL10n.createElement(doc, "div");
-    messageEl.classList.add("whatsNew-message");
-
-    // Only render date if it is different from the one rendered before.
-    if (content.published_date !== previousDate) {
-      messageEl.appendChild(
-        lazy.RemoteL10n.createElement(doc, "p", {
-          classList: "whatsNew-message-date",
-          content: new Date(content.published_date).toLocaleDateString(
-            "default",
-            {
-              month: "long",
-              day: "numeric",
-              year: "numeric",
-            }
-          ),
-        })
-      );
-    }
-
-    const wrapperEl = lazy.RemoteL10n.createElement(doc, "div");
-    wrapperEl.doCommand = () => this._dispatchUserAction(win, message);
-    wrapperEl.classList.add("whatsNew-message-body");
-    messageEl.appendChild(wrapperEl);
-
-    if (content.icon_url) {
-      wrapperEl.classList.add("has-icon");
-      const iconEl = lazy.RemoteL10n.createElement(doc, "img");
-      iconEl.src = content.icon_url;
-      iconEl.classList.add("whatsNew-message-icon");
-      if (content.icon_alt && content.icon_alt.string_id) {
-        doc.l10n.setAttributes(iconEl, content.icon_alt.string_id);
-      } else {
-        iconEl.setAttribute("alt", content.icon_alt);
-      }
-      wrapperEl.appendChild(iconEl);
-    }
-
-    wrapperEl.appendChild(this._createMessageContent(win, doc, content));
-
-    if (content.link_text) {
-      const anchorEl = lazy.RemoteL10n.createElement(doc, "a", {
-        classList: "text-link",
-        content: content.link_text,
-      });
-      anchorEl.doCommand = () => this._dispatchUserAction(win, message);
-      wrapperEl.appendChild(anchorEl);
-    }
-
-    // Attach event listener on entire message container
-    this._attachCommandListener(win, messageEl, message);
-
-    return messageEl;
-  }
-
-  /**
-   * Return message title (optional subtitle) and body
-   */
-  _createMessageContent(win, doc, content) {
-    const wrapperEl = new win.DocumentFragment();
-
-    wrapperEl.appendChild(
-      lazy.RemoteL10n.createElement(doc, "h2", {
-        classList: "whatsNew-message-title",
-        content: content.title,
-        attributes: this.state.contentArguments,
-      })
-    );
-
-    wrapperEl.appendChild(
-      lazy.RemoteL10n.createElement(doc, "p", {
-        content: content.body,
-        classList: "whatsNew-message-content",
-        attributes: this.state.contentArguments,
-      })
-    );
-
-    return wrapperEl;
-  }
-
-  _createHeroElement(win, doc, message) {
-    this.maybeLoadCustomElement(win);
-
-    const messageEl = lazy.RemoteL10n.createElement(doc, "div");
-    messageEl.setAttribute("id", "protections-popup-message");
-    messageEl.classList.add("whatsNew-hero-message");
-    const wrapperEl = lazy.RemoteL10n.createElement(doc, "div");
-    wrapperEl.classList.add("whatsNew-message-body");
-    messageEl.appendChild(wrapperEl);
-
-    wrapperEl.appendChild(
-      lazy.RemoteL10n.createElement(doc, "h2", {
-        classList: "whatsNew-message-title",
-        content: message.content.title,
-      })
-    );
-    wrapperEl.appendChild(
-      lazy.RemoteL10n.createElement(doc, "p", {
-        classList: "protections-popup-content",
-        content: message.content.body,
-      })
-    );
-
-    if (message.content.link_text) {
-      let linkEl = lazy.RemoteL10n.createElement(doc, "a", {
-        classList: "text-link",
-        content: message.content.link_text,
-      });
-      linkEl.disabled = true;
-      wrapperEl.appendChild(linkEl);
-      this._attachCommandListener(win, linkEl, message);
-    } else {
-      this._attachCommandListener(win, wrapperEl, message);
-    }
-
-    return messageEl;
-  }
-
-  async _contentArguments() {
-    const { defaultEngine } = Services.search;
-    // Between now and 6 weeks ago
-    const dateTo = new Date();
-    const dateFrom = new Date(dateTo.getTime() - 42 * 24 * 60 * 60 * 1000);
-    const eventsByDate = await lazy.TrackingDBService.getEventsByDateRange(
-      dateFrom,
-      dateTo
-    );
-    // Make sure we set all types of possible values to 0 because they might
-    // be referenced by fluent strings
-    let totalEvents = { blockedCount: 0 };
-    for (let blockedType of idToTextMap.values()) {
-      totalEvents[blockedType] = 0;
-    }
-    // Count all events in the past 6 weeks. Returns an object with:
-    // `blockedCount` total number of blocked resources
-    // {tracker|cookie|social...} breakdown by event type as defined by `idToTextMap`
-    totalEvents = eventsByDate.reduce((acc, day) => {
-      const type = day.getResultByName("type");
-      const count = day.getResultByName("count");
-      acc[idToTextMap.get(type)] = (acc[idToTextMap.get(type)] || 0) + count;
-      acc.blockedCount += count;
-      return acc;
-    }, totalEvents);
-    return {
-      // Keys need to match variable names used in asrouter.ftl
-      // `earliestDate` will be either 6 weeks ago or when tracking recording
-      // started. Whichever is more recent.
-      earliestDate: Math.max(
-        new Date(await lazy.TrackingDBService.getEarliestRecordedDate()),
-        dateFrom
-      ),
-      ...totalEvents,
-      // Passing in `undefined` as string for the Fluent variable name
-      // in order to match and select the message that does not require
-      // the variable.
-      searchEngineName: defaultEngine ? defaultEngine.name : "undefined",
-    };
-  }
-
-  async _showAppmenuButton(win) {
-    this.maybeInsertFTL(win);
-    await this._showElement(
-      win.browser.ownerDocument,
-      APPMENU_BUTTON_ID,
-      BUTTON_STRING_ID
-    );
-  }
-
-  _hideAppmenuButton(win, windowClosed) {
-    // No need to do something if the window is going away
-    if (!windowClosed) {
-      this._hideElement(win.browser.ownerDocument, APPMENU_BUTTON_ID);
-    }
-  }
-
-  _showToolbarButton(win) {
-    const document = win.browser.ownerDocument;
-    this.maybeInsertFTL(win);
-    return this._showElement(document, TOOLBAR_BUTTON_ID, BUTTON_STRING_ID);
-  }
-
-  _hideToolbarButton(win) {
-    this._hideElement(win.browser.ownerDocument, TOOLBAR_BUTTON_ID);
-  }
-
-  _showElement(document, id, string_id) {
-    const el = lazy.PanelMultiView.getViewNode(document, id);
-    document.l10n.setAttributes(el, string_id);
-    el.hidden = false;
-  }
-
-  _hideElement(document, id) {
-    const el = lazy.PanelMultiView.getViewNode(document, id);
-    if (el) {
-      el.hidden = true;
-    }
-  }
-
-  _sendPing(ping) {
-    this._sendTelemetry({
-      type: "TOOLBAR_PANEL_TELEMETRY",
-      data: { action: "whats-new-panel_user_event", ...ping },
-    });
-  }
-
-  sendUserEventTelemetry(win, event, message, options = {}) {
-    // Only send pings for non private browsing windows
-    if (
-      win &&
-      !lazy.PrivateBrowsingUtils.isBrowserPrivate(
-        win.ownerGlobal.gBrowser.selectedBrowser
-      )
-    ) {
-      this._sendPing({
-        message_id: message.id,
-        event,
-        event_context: options.value,
-      });
-    }
-  }
-
-  /**
-   * @param {object} [browser] MessageChannel target argument as a response to a
-   *   user action. No message is shown if undefined.
-   * @param {object[]} messages Messages selected from devtools page
-   */
-  forceShowMessage(browser, messages) {
-    if (!browser) {
-      return;
-    }
-    const win = browser.ownerGlobal;
-    const doc = browser.ownerDocument;
-    this.removeMessages(win, WHATS_NEW_PANEL_SELECTOR);
-    this.renderMessages(win, doc, WHATS_NEW_PANEL_SELECTOR, {
-      force: true,
-      messages: Array.isArray(messages) ? messages : [messages],
-    });
-    win.PanelUI.panel.addEventListener("popuphidden", event =>
-      this.removeMessages(event.target.ownerGlobal, WHATS_NEW_PANEL_SELECTOR)
-    );
-  }
-}
-
-/**
- * ToolbarPanelHub - singleton instance of _ToolbarPanelHub that can initiate
- * message requests and render messages.
- */
-export const ToolbarPanelHub = new _ToolbarPanelHub();
diff --git a/browser/components/asrouter/moz.build b/browser/components/asrouter/moz.build
index 558ccbeb9b..cf45186619 100644
--- a/browser/components/asrouter/moz.build
+++ b/browser/components/asrouter/moz.build
@@ -15,7 +15,7 @@ FINAL_TARGET_FILES.actors += [
 ]
 
 EXTRA_JS_MODULES.asrouter += [
-    "modules/ActorConstants.sys.mjs",
+    "modules/ActorConstants.mjs",
     "modules/ASRouter.sys.mjs",
     "modules/ASRouterDefaultConfig.sys.mjs",
     "modules/ASRouterNewTabHook.sys.mjs",
@@ -38,7 +38,6 @@ EXTRA_JS_MODULES.asrouter += [
     "modules/Spotlight.sys.mjs",
     "modules/ToastNotification.sys.mjs",
     "modules/ToolbarBadgeHub.sys.mjs",
-    "modules/ToolbarPanelHub.sys.mjs",
 ]
 
 BROWSER_CHROME_MANIFESTS += [
@@ -57,7 +56,6 @@ TESTING_JS_MODULES += [
     "content-src/templates/OnboardingMessage/Spotlight.schema.json",
     "content-src/templates/OnboardingMessage/ToolbarBadgeMessage.schema.json",
     "content-src/templates/OnboardingMessage/UpdateAction.schema.json",
-    "content-src/templates/OnboardingMessage/WhatsNewMessage.schema.json",
     "content-src/templates/PBNewtab/NewtabPromoMessage.schema.json",
     "content-src/templates/ToastNotification/ToastNotification.schema.json",
     "tests/InflightAssetsMessageProvider.sys.mjs",
diff --git a/browser/components/asrouter/package.json b/browser/components/asrouter/package.json
index 17bc8f7364..26c09392c2 100644
--- a/browser/components/asrouter/package.json
+++ b/browser/components/asrouter/package.json
@@ -60,6 +60,7 @@
     "testmc:lint": "npm run lint",
     "testmc:build": "npm run bundle:admin",
     "testmc:unit": "karma start karma.mc.config.js",
+    "testmc:import": "npm run import-rollouts",
     "tddmc": "karma start karma.mc.config.js --tdd",
     "debugcoverage": "open logs/coverage/lcov-report/index.html",
     "lint": "npm-run-all lint:*",
diff --git a/browser/components/asrouter/tests/InflightAssetsMessageProvider.sys.mjs b/browser/components/asrouter/tests/InflightAssetsMessageProvider.sys.mjs
index e92b210c12..adb14ecc38 100644
--- a/browser/components/asrouter/tests/InflightAssetsMessageProvider.sys.mjs
+++ b/browser/components/asrouter/tests/InflightAssetsMessageProvider.sys.mjs
@@ -10,58 +10,10 @@ export const InflightAssetsMessageProvider = {
   getMessages() {
     return [
       {
-        id: "MILESTONE_MESSAGE",
-        groups: ["cfr"],
-        content: {
-          anchor_id: "tracking-protection-icon-box",
-          bucket_id: "CFR_MILESTONE_MESSAGE",
-          buttons: {
-            primary: {
-              action: {
-                type: "OPEN_PROTECTION_REPORT",
-              },
-              event: "PROTECTION",
-              label: {
-                string_id: "cfr-doorhanger-milestone-ok-button",
-              },
-            },
-            secondary: [
-              {
-                label: {
-                  string_id: "cfr-doorhanger-milestone-close-button",
-                },
-                action: {
-                  type: "CANCEL",
-                },
-                event: "DISMISS",
-              },
-            ],
-          },
-          category: "cfrFeatures",
-          heading_text: {
-            string_id: "cfr-doorhanger-milestone-heading",
-          },
-          layout: "short_message",
-          notification_text: "",
-          skip_address_bar_notifier: true,
-          text: "",
-        },
-        frequency: {
-          lifetime: 7,
-        },
-        targeting:
-          "pageLoad >= 4 && firefoxVersion < 87 && userPrefs.cfrFeatures",
-        template: "milestone_message",
-        trigger: {
-          id: "contentBlocking",
-          params: ["ContentBlockingMilestone"],
-        },
-      },
-      {
         id: "MILESTONE_MESSAGE_87",
         groups: ["cfr"],
         content: {
-          anchor_id: "tracking-protection-icon-box",
+          anchor_id: "tracking-protection-icon-container",
           bucket_id: "CFR_MILESTONE_MESSAGE",
           buttons: {
             primary: {
@@ -98,7 +50,7 @@ export const InflightAssetsMessageProvider = {
           lifetime: 7,
         },
         targeting:
-          "pageLoad >= 4 && firefoxVersion >= 87 && userPrefs.cfrFeatures",
+          "pageLoad >= 4 && firefoxVersion >= 115 && firefoxVersion < 121 && userPrefs.cfrFeatures",
         template: "milestone_message",
         trigger: {
           id: "contentBlocking",
@@ -275,66 +227,6 @@ export const InflightAssetsMessageProvider = {
           ],
         },
       },
-      {
-        id: "WNP_MOMENTS_12",
-        groups: ["moments-pages"],
-        content: {
-          action: {
-            data: {
-              expire: 1640908800000,
-              url: "https://www.mozilla.org/firefox/welcome/12",
-            },
-            id: "moments-wnp",
-          },
-          bucket_id: "WNP_MOMENTS_12",
-        },
-        targeting:
-          'localeLanguageCode == "en" && region in ["DE", "AT", "BE", "CA", "FR", "IE", "IT", "MY", "NL", "NZ", "SG", "CH", "US", "GB", "ES"]  && (addonsInfo.addons|keys intersect ["@testpilot-containers"])|length == 1 && \'browser.newtabpage.activity-stream.asrouter.userprefs.cfr.features\'|preferenceValue && \'browser.newtabpage.activity-stream.asrouter.userprefs.cfr.addons\'|preferenceValue',
-        template: "update_action",
-        trigger: {
-          id: "momentsUpdate",
-        },
-      },
-      {
-        id: "WNP_MOMENTS_13",
-        groups: ["moments-pages"],
-        content: {
-          action: {
-            data: {
-              expire: 1640908800000,
-              url: "https://www.mozilla.org/firefox/welcome/13",
-            },
-            id: "moments-wnp",
-          },
-          bucket_id: "WNP_MOMENTS_13",
-        },
-        targeting:
-          '(localeLanguageCode in ["en", "de", "fr", "nl", "it", "ms"] || locale == "es-ES") && region in ["DE", "AT", "BE", "CA", "FR", "IE", "IT", "MY", "NL", "NZ", "SG", "CH", "US", "GB", "ES"]  && (addonsInfo.addons|keys intersect ["@testpilot-containers"])|length == 0 && \'browser.newtabpage.activity-stream.asrouter.userprefs.cfr.features\'|preferenceValue && \'browser.newtabpage.activity-stream.asrouter.userprefs.cfr.addons\'|preferenceValue',
-        template: "update_action",
-        trigger: {
-          id: "momentsUpdate",
-        },
-      },
-      {
-        id: "WNP_MOMENTS_14",
-        groups: ["moments-pages"],
-        content: {
-          action: {
-            data: {
-              expire: 1668470400000,
-              url: "https://www.mozilla.org/firefox/welcome/14",
-            },
-            id: "moments-wnp",
-          },
-          bucket_id: "WNP_MOMENTS_14",
-        },
-        targeting:
-          'localeLanguageCode in ["en", "de", "fr"] && region in ["AT", "BE", "CA", "CH", "DE", "ES", "FI", "FR", "GB", "IE", "IT", "MY", "NL", "NZ", "SE", "SG", "US"]  && \'browser.newtabpage.activity-stream.asrouter.userprefs.cfr.features\'|preferenceValue && \'browser.newtabpage.activity-stream.asrouter.userprefs.cfr.addons\'|preferenceValue',
-        template: "update_action",
-        trigger: {
-          id: "momentsUpdate",
-        },
-      },
     ];
   },
 };
diff --git a/browser/components/asrouter/tests/NimbusRolloutMessageProvider.sys.mjs b/browser/components/asrouter/tests/NimbusRolloutMessageProvider.sys.mjs
index 5bfbec9557..f2c94f7de6 100644
--- a/browser/components/asrouter/tests/NimbusRolloutMessageProvider.sys.mjs
+++ b/browser/components/asrouter/tests/NimbusRolloutMessageProvider.sys.mjs
@@ -12,6 +12,427 @@ export const NimbusRolloutMessageProvider = {
   getMessages() {
     return [
       {
+        // Nimbus slug: device-migration-q4-spotlights-remaining-population-esr:treatment (message 1 of 3)
+        // Recipe: https://experimenter.services.mozilla.com/nimbus/device-migration-q4-spotlights-remaining-population-esr/summary#treatment
+        id: "Q4_DEVICE_MIGRATION_BACKUP_SPOTLIGHT",
+        groups: ["eco"],
+        content: {
+          id: "Q4_DEVICE_MIGRATION_BACKUP_SPOTLIGHT",
+          modal: "tab",
+          screens: [
+            {
+              id: "Q4_DEVICE_MIGRATION_BACKUP_SPOTLIGHT_BACKUP",
+              content: {
+                logo: {
+                  height: "152px",
+                  imageURL:
+                    "https://firefox-settings-attachments.cdn.mozilla.net/main-workspace/ms-images/c92a41e4-82cf-4ad5-8480-04a138bfb3cd.png",
+                },
+                title: {
+                  fontSize: "24px",
+                  string_id: "device-migration-fxa-spotlight-heavy-user-header",
+                  letterSpacing: 0,
+                },
+                subtitle: {
+                  fontSize: "15px",
+                  string_id: "device-migration-fxa-spotlight-heavy-user-body",
+                  lineHeight: "1.4",
+                  marginBlock: "8px 20px",
+                  letterSpacing: 0,
+                  paddingInline: "20px",
+                },
+                dismiss_button: {
+                  action: {
+                    navigate: true,
+                  },
+                },
+                primary_button: {
+                  label: {
+                    string_id:
+                      "device-migration-fxa-spotlight-heavy-user-primary-button",
+                    paddingBlock: "4px",
+                    paddingInline: "16px",
+                  },
+                  action: {
+                    data: {
+                      args: "https://support.mozilla.org/1/firefox/%VERSION%/%OS%/%LOCALE%/switching-devices?utm_source=spotlight-default&utm_medium=firefox-desktop&utm_campaign=migration&utm_content=dont-forget-to-backup&entrypoint=device-migration-spotlight-experiment-v2",
+                      where: "tabshifted",
+                    },
+                    type: "OPEN_URL",
+                    navigate: true,
+                  },
+                },
+              },
+            },
+          ],
+          backdrop: "transparent",
+          template: "multistage",
+          transitions: true,
+        },
+        trigger: {
+          id: "defaultBrowserCheck",
+        },
+        template: "spotlight",
+        frequency: {
+          lifetime: 1,
+        },
+        targeting:
+          "source == 'startup' && !willShowDefaultPrompt && 'browser.newtabpage.activity-stream.asrouter.userprefs.cfr.features'|preferenceValue && !usesFirefoxSync && !hasActiveEnterprisePolicies && userMonthlyActivity[userMonthlyActivity|length - 2][1]|date >= currentDate|date - (28 * 24 * 60 * 60 * 1000) && (((currentDate|date - profileAgeCreated|date) / 86400000 >= 168) || totalBookmarksCount >= 35)",
+      },
+      {
+        // Nimbus slug: device-migration-q4-spotlights-remaining-population-esr:treatment (message 2 of 3)
+        // Recipe: https://experimenter.services.mozilla.com/nimbus/device-migration-q4-spotlights-remaining-population-esr/summary#treatment
+        id: "Q4_DEVICE_MIGRATION_BACKUP_SPOTLIGHT",
+        groups: ["eco"],
+        content: {
+          id: "Q4_DEVICE_MIGRATION_BACKUP_SPOTLIGHT",
+          modal: "tab",
+          screens: [
+            {
+              id: "Q4_DEVICE_MIGRATION_BACKUP_SPOTLIGHT_PEACE",
+              content: {
+                logo: {
+                  height: "133px",
+                  imageURL:
+                    "https://firefox-settings-attachments.cdn.mozilla.net/main-workspace/ms-images/4a56d3ed-98c8-4a33-b853-b2cf7646efd8.png",
+                  marginBlock: "22px -10px",
+                },
+                title: {
+                  fontSize: "24px",
+                  string_id:
+                    "device-migration-fxa-spotlight-older-device-header",
+                  letterSpacing: 0,
+                },
+                subtitle: {
+                  fontSize: "15px",
+                  string_id: "device-migration-fxa-spotlight-older-device-body",
+                  lineHeight: "1.4",
+                  marginBlock: "8px 20px",
+                  letterSpacing: 0,
+                  paddingInline: "40px",
+                },
+                dismiss_button: {
+                  action: {
+                    navigate: true,
+                  },
+                },
+                primary_button: {
+                  label: {
+                    string_id:
+                      "device-migration-fxa-spotlight-older-device-primary-button",
+                    marginBlock: "0 22px",
+                    paddingBlock: "4px",
+                    paddingInline: "16px",
+                  },
+                  action: {
+                    data: {
+                      args: "https://support.mozilla.org/1/firefox/%VERSION%/%OS%/%LOCALE%/switching-devices?utm_source=spotlight-default&utm_medium=firefox-desktop&utm_campaign=migration&utm_content=peace-of-mind&entrypoint=device-migration-spotlight-experiment-v2",
+                      where: "tabshifted",
+                    },
+                    type: "OPEN_URL",
+                    navigate: true,
+                  },
+                },
+              },
+            },
+          ],
+          backdrop: "transparent",
+          template: "multistage",
+          transitions: true,
+        },
+        trigger: {
+          id: "defaultBrowserCheck",
+        },
+        template: "spotlight",
+        frequency: {
+          lifetime: 1,
+        },
+        targeting:
+          "source == 'startup' && !willShowDefaultPrompt && 'browser.newtabpage.activity-stream.asrouter.userprefs.cfr.features'|preferenceValue && !usesFirefoxSync && !hasActiveEnterprisePolicies && userMonthlyActivity[userMonthlyActivity|length - 2][1]|date >= currentDate|date - (28 * 24 * 60 * 60 * 1000) && !(((currentDate|date - profileAgeCreated|date) / 86400000 >= 168) || totalBookmarksCount >= 35) && os.isWindows && os.windowsVersion >= 6.1 && os.windowsBuildNumber < 22000",
+      },
+      {
+        // Nimbus slug: device-migration-q4-spotlights-remaining-population-esr:treatment (message 3 of 3)
+        // Recipe: https://experimenter.services.mozilla.com/nimbus/device-migration-q4-spotlights-remaining-population-esr/summary#treatment
+        id: "Q4_DEVICE_MIGRATION_BACKUP_SPOTLIGHT",
+        groups: ["eco"],
+        content: {
+          id: "Q4_DEVICE_MIGRATION_BACKUP_SPOTLIGHT",
+          modal: "tab",
+          screens: [
+            {
+              id: "Q4_DEVICE_MIGRATION_BACKUP_SPOTLIGHT_NEW_DEVICE",
+              content: {
+                logo: {
+                  height: "149px",
+                  imageURL:
+                    "https://firefox-settings-attachments.cdn.mozilla.net/main-workspace/ms-images/a43cd9cc-e8b2-477c-92f2-345557370de1.svg",
+                },
+                title: {
+                  fontSize: "24px",
+                  string_id:
+                    "device-migration-fxa-spotlight-getting-new-device-header-2",
+                  letterSpacing: 0,
+                },
+                subtitle: {
+                  fontSize: "15px",
+                  string_id:
+                    "device-migration-fxa-spotlight-getting-new-device-body-2",
+                  lineHeight: "1.4",
+                  marginBlock: "8px 20px",
+                  letterSpacing: 0,
+                  paddingInline: "40px",
+                },
+                dismiss_button: {
+                  action: {
+                    navigate: true,
+                  },
+                },
+                primary_button: {
+                  label: {
+                    string_id:
+                      "device-migration-fxa-spotlight-getting-new-device-primary-button",
+                    paddingBlock: "4px",
+                    paddingInline: "16px",
+                  },
+                  action: {
+                    data: {
+                      args: "https://support.mozilla.org/1/firefox/%VERSION%/%OS%/%LOCALE%/switching-devices?utm_source=spotlight-default&utm_medium=firefox-desktop&utm_campaign=migration&utm_content=new-device-in-your-future&entrypoint=device-migration-spotlight-experiment-v2",
+                      where: "tabshifted",
+                    },
+                    type: "OPEN_URL",
+                    navigate: true,
+                  },
+                },
+              },
+            },
+          ],
+          backdrop: "transparent",
+          template: "multistage",
+          transitions: true,
+        },
+        trigger: {
+          id: "defaultBrowserCheck",
+        },
+        template: "spotlight",
+        frequency: {
+          lifetime: 1,
+        },
+        targeting:
+          "source == 'startup' && !willShowDefaultPrompt && 'browser.newtabpage.activity-stream.asrouter.userprefs.cfr.features'|preferenceValue && !usesFirefoxSync && !hasActiveEnterprisePolicies && userMonthlyActivity[userMonthlyActivity|length - 2][1]|date >= currentDate|date - (28 * 24 * 60 * 60 * 1000) && !(((currentDate|date - profileAgeCreated|date) / 86400000 >= 168) || totalBookmarksCount >= 35) && !(os.isWindows && os.windowsVersion >= 6.1 && os.windowsBuildNumber < 22000)",
+      },
+      {
+        // Nimbus slug: device-migration-q4-spotlights-remaining-population:treatment (message 1 of 3)
+        // Version range: 122+
+        // Recipe: https://experimenter.services.mozilla.com/nimbus/device-migration-q4-spotlights-remaining-population/summary#treatment
+        id: "Q4_DEVICE_MIGRATION_BACKUP_SPOTLIGHT",
+        groups: ["eco"],
+        content: {
+          id: "Q4_DEVICE_MIGRATION_BACKUP_SPOTLIGHT",
+          modal: "tab",
+          screens: [
+            {
+              id: "Q4_DEVICE_MIGRATION_BACKUP_SPOTLIGHT_BACKUP",
+              content: {
+                logo: {
+                  height: "152px",
+                  imageURL:
+                    "https://firefox-settings-attachments.cdn.mozilla.net/main-workspace/ms-images/c92a41e4-82cf-4ad5-8480-04a138bfb3cd.png",
+                },
+                title: {
+                  fontSize: "24px",
+                  string_id: "device-migration-fxa-spotlight-heavy-user-header",
+                  letterSpacing: 0,
+                },
+                subtitle: {
+                  fontSize: "15px",
+                  string_id: "device-migration-fxa-spotlight-heavy-user-body",
+                  lineHeight: "1.4",
+                  marginBlock: "8px 20px",
+                  letterSpacing: 0,
+                  paddingInline: "20px",
+                },
+                dismiss_button: {
+                  action: {
+                    navigate: true,
+                  },
+                },
+                primary_button: {
+                  label: {
+                    string_id:
+                      "device-migration-fxa-spotlight-heavy-user-primary-button",
+                    paddingBlock: "4px",
+                    paddingInline: "16px",
+                  },
+                  action: {
+                    data: {
+                      args: "https://support.mozilla.org/1/firefox/%VERSION%/%OS%/%LOCALE%/switching-devices?utm_source=spotlight-default&utm_medium=firefox-desktop&utm_campaign=migration&utm_content=dont-forget-to-backup&entrypoint=device-migration-spotlight-experiment-v2",
+                      where: "tabshifted",
+                    },
+                    type: "OPEN_URL",
+                    navigate: true,
+                  },
+                },
+              },
+            },
+          ],
+          backdrop: "transparent",
+          template: "multistage",
+          transitions: true,
+        },
+        trigger: {
+          id: "defaultBrowserCheck",
+        },
+        template: "spotlight",
+        frequency: {
+          lifetime: 1,
+        },
+        targeting:
+          "source == 'startup' && !willShowDefaultPrompt && 'browser.newtabpage.activity-stream.asrouter.userprefs.cfr.features'|preferenceValue && !usesFirefoxSync && !hasActiveEnterprisePolicies && userMonthlyActivity[userMonthlyActivity|length - 2][1]|date >= currentDate|date - (28 * 24 * 60 * 60 * 1000) && (((currentDate|date - profileAgeCreated|date) / 86400000 >= 168) || totalBookmarksCount >= 35)",
+      },
+      {
+        // Nimbus slug: device-migration-q4-spotlights-remaining-population:treatment (message 2 of 3)
+        // Version range: 122+
+        // Recipe: https://experimenter.services.mozilla.com/nimbus/device-migration-q4-spotlights-remaining-population/summary#treatment
+        id: "Q4_DEVICE_MIGRATION_BACKUP_SPOTLIGHT",
+        groups: ["eco"],
+        content: {
+          id: "Q4_DEVICE_MIGRATION_BACKUP_SPOTLIGHT",
+          modal: "tab",
+          screens: [
+            {
+              id: "Q4_DEVICE_MIGRATION_BACKUP_SPOTLIGHT_PEACE",
+              content: {
+                logo: {
+                  height: "133px",
+                  imageURL:
+                    "https://firefox-settings-attachments.cdn.mozilla.net/main-workspace/ms-images/4a56d3ed-98c8-4a33-b853-b2cf7646efd8.png",
+                  marginBlock: "22px -10px",
+                },
+                title: {
+                  fontSize: "24px",
+                  string_id:
+                    "device-migration-fxa-spotlight-older-device-header",
+                  letterSpacing: 0,
+                },
+                subtitle: {
+                  fontSize: "15px",
+                  string_id: "device-migration-fxa-spotlight-older-device-body",
+                  lineHeight: "1.4",
+                  marginBlock: "8px 20px",
+                  letterSpacing: 0,
+                  paddingInline: "40px",
+                },
+                dismiss_button: {
+                  action: {
+                    navigate: true,
+                  },
+                },
+                primary_button: {
+                  label: {
+                    string_id:
+                      "device-migration-fxa-spotlight-older-device-primary-button",
+                    marginBlock: "0 22px",
+                    paddingBlock: "4px",
+                    paddingInline: "16px",
+                  },
+                  action: {
+                    data: {
+                      args: "https://support.mozilla.org/1/firefox/%VERSION%/%OS%/%LOCALE%/switching-devices?utm_source=spotlight-default&utm_medium=firefox-desktop&utm_campaign=migration&utm_content=peace-of-mind&entrypoint=device-migration-spotlight-experiment-v2",
+                      where: "tabshifted",
+                    },
+                    type: "OPEN_URL",
+                    navigate: true,
+                  },
+                },
+              },
+            },
+          ],
+          backdrop: "transparent",
+          template: "multistage",
+          transitions: true,
+        },
+        trigger: {
+          id: "defaultBrowserCheck",
+        },
+        template: "spotlight",
+        frequency: {
+          lifetime: 1,
+        },
+        targeting:
+          "source == 'startup' && !willShowDefaultPrompt && 'browser.newtabpage.activity-stream.asrouter.userprefs.cfr.features'|preferenceValue && !usesFirefoxSync && !hasActiveEnterprisePolicies && userMonthlyActivity[userMonthlyActivity|length - 2][1]|date >= currentDate|date - (28 * 24 * 60 * 60 * 1000) && !(((currentDate|date - profileAgeCreated|date) / 86400000 >= 168) || totalBookmarksCount >= 35) && os.isWindows && os.windowsVersion >= 6.1 && os.windowsBuildNumber < 22000",
+      },
+      {
+        // Nimbus slug: device-migration-q4-spotlights-remaining-population:treatment (message 3 of 3)
+        // Version range: 122+
+        // Recipe: https://experimenter.services.mozilla.com/nimbus/device-migration-q4-spotlights-remaining-population/summary#treatment
+        id: "Q4_DEVICE_MIGRATION_BACKUP_SPOTLIGHT",
+        groups: ["eco"],
+        content: {
+          id: "Q4_DEVICE_MIGRATION_BACKUP_SPOTLIGHT",
+          modal: "tab",
+          screens: [
+            {
+              id: "Q4_DEVICE_MIGRATION_BACKUP_SPOTLIGHT_NEW_DEVICE",
+              content: {
+                logo: {
+                  height: "149px",
+                  imageURL:
+                    "https://firefox-settings-attachments.cdn.mozilla.net/main-workspace/ms-images/a43cd9cc-e8b2-477c-92f2-345557370de1.svg",
+                },
+                title: {
+                  fontSize: "24px",
+                  string_id:
+                    "device-migration-fxa-spotlight-getting-new-device-header-2",
+                  letterSpacing: 0,
+                },
+                subtitle: {
+                  fontSize: "15px",
+                  string_id:
+                    "device-migration-fxa-spotlight-getting-new-device-body-2",
+                  lineHeight: "1.4",
+                  marginBlock: "8px 20px",
+                  letterSpacing: 0,
+                  paddingInline: "40px",
+                },
+                dismiss_button: {
+                  action: {
+                    navigate: true,
+                  },
+                },
+                primary_button: {
+                  label: {
+                    string_id:
+                      "device-migration-fxa-spotlight-getting-new-device-primary-button",
+                    paddingBlock: "4px",
+                    paddingInline: "16px",
+                  },
+                  action: {
+                    data: {
+                      args: "https://support.mozilla.org/1/firefox/%VERSION%/%OS%/%LOCALE%/switching-devices?utm_source=spotlight-default&utm_medium=firefox-desktop&utm_campaign=migration&utm_content=new-device-in-your-future&entrypoint=device-migration-spotlight-experiment-v2",
+                      where: "tabshifted",
+                    },
+                    type: "OPEN_URL",
+                    navigate: true,
+                  },
+                },
+              },
+            },
+          ],
+          backdrop: "transparent",
+          template: "multistage",
+          transitions: true,
+        },
+        trigger: {
+          id: "defaultBrowserCheck",
+        },
+        template: "spotlight",
+        frequency: {
+          lifetime: 1,
+        },
+        targeting:
+          "source == 'startup' && !willShowDefaultPrompt && 'browser.newtabpage.activity-stream.asrouter.userprefs.cfr.features'|preferenceValue && !usesFirefoxSync && !hasActiveEnterprisePolicies && userMonthlyActivity[userMonthlyActivity|length - 2][1]|date >= currentDate|date - (28 * 24 * 60 * 60 * 1000) && !(((currentDate|date - profileAgeCreated|date) / 86400000 >= 168) || totalBookmarksCount >= 35) && !(os.isWindows && os.windowsVersion >= 6.1 && os.windowsBuildNumber < 22000)",
+      },
+      {
         // Nimbus slug: fox-doodle-set-to-default-early-day-user-de-fr-it-treatment-a-rollout:treatment-a
         // Version range: 116+
         // Recipe: https://experimenter.services.mozilla.com/nimbus/fox-doodle-set-to-default-early-day-user-de-fr-it-treatment-a-rollout/summary#treatment-a
diff --git a/browser/components/asrouter/tests/browser/browser.toml b/browser/components/asrouter/tests/browser/browser.toml
index 7bed40373d..60ce42dfd8 100644
--- a/browser/components/asrouter/tests/browser/browser.toml
+++ b/browser/components/asrouter/tests/browser/browser.toml
@@ -21,6 +21,11 @@ skip-if = ["os == 'linux' && bits == 64 && !debug"] # Bug 1643036
 
 ["browser_asrouter_infobar.js"]
 
+["browser_asrouter_keyboard_cfr.js"]
+https_first_disabled = true
+
+["browser_asrouter_milestone_message_cfr.js"]
+
 ["browser_asrouter_momentspagehub.js"]
 tags = "remote-settings"
 
diff --git a/browser/components/asrouter/tests/browser/browser_asrouter_bug1761522.js b/browser/components/asrouter/tests/browser/browser_asrouter_bug1761522.js
index 19fcb63131..d22605d589 100644
--- a/browser/components/asrouter/tests/browser/browser_asrouter_bug1761522.js
+++ b/browser/components/asrouter/tests/browser/browser_asrouter_bug1761522.js
@@ -20,7 +20,7 @@ const { RemoteSettings } = ChromeUtils.importESModule(
 );
 
 // This pref is used to override the Remote Settings server URL in tests.
-// See SERVER_URL in services/settings/Utils.jsm for more details.
+// See SERVER_URL in services/settings/Utils.sys.mjs for more details.
 const RS_SERVER_PREF = "services.settings.server";
 
 const FLUENT_CONTENT = "asrouter-test-string = Test Test Test\n";
diff --git a/browser/components/asrouter/tests/browser/browser_asrouter_cfr.js b/browser/components/asrouter/tests/browser/browser_asrouter_cfr.js
index e29771c24f..1979c81a79 100644
--- a/browser/components/asrouter/tests/browser/browser_asrouter_cfr.js
+++ b/browser/components/asrouter/tests/browser/browser_asrouter_cfr.js
@@ -115,14 +115,6 @@ function checkCFRAddonsElements(notification) {
   );
 }
 
-function checkCFRTrackingProtectionMilestone(notification) {
-  Assert.ok(notification.hidden === false, "Panel should be visible");
-  Assert.ok(
-    notification.getAttribute("data-notification-category") === "short_message",
-    "Panel have correct data attribute"
-  );
-}
-
 function clearNotifications() {
   for (let notification of PopupNotifications._currentNotifications) {
     notification.remove();
@@ -498,59 +490,6 @@ add_task(async function test_cfr_addon_install() {
   Services.fog.testResetFOG();
 });
 
-add_task(
-  async function test_cfr_tracking_protection_milestone_notification_remove() {
-    await SpecialPowers.pushPrefEnv({
-      set: [
-        ["browser.contentblocking.cfr-milestone.milestone-achieved", 1000],
-        [
-          "browser.newtabpage.activity-stream.asrouter.providers.cfr",
-          `{"id":"cfr","enabled":true,"type":"local","localProvider":"CFRMessageProvider","updateCycleInMs":3600000}`,
-        ],
-      ],
-    });
-
-    // addRecommendation checks that scheme starts with http and host matches
-    let browser = gBrowser.selectedBrowser;
-    BrowserTestUtils.startLoadingURIString(browser, "http://example.com/");
-    await BrowserTestUtils.browserLoaded(browser, false, "http://example.com/");
-
-    const showPanel = BrowserTestUtils.waitForEvent(
-      PopupNotifications.panel,
-      "popupshown"
-    );
-
-    Services.obs.notifyObservers(
-      {
-        wrappedJSObject: {
-          event: "ContentBlockingMilestone",
-        },
-      },
-      "SiteProtection:ContentBlockingMilestone"
-    );
-
-    await showPanel;
-
-    const notification = document.getElementById(
-      "contextual-feature-recommendation-notification"
-    );
-
-    checkCFRTrackingProtectionMilestone(notification);
-
-    Assert.ok(notification.secondaryButton);
-    let hidePanel = BrowserTestUtils.waitForEvent(
-      PopupNotifications.panel,
-      "popuphidden"
-    );
-
-    notification.secondaryButton.click();
-    await hidePanel;
-    await SpecialPowers.popPrefEnv();
-    clearNotifications();
-    Services.fog.testResetFOG();
-  }
-);
-
 add_task(async function test_cfr_addon_and_features_show() {
   // addRecommendation checks that scheme starts with http and host matches
   let browser = gBrowser.selectedBrowser;
@@ -747,62 +686,6 @@ add_task(async function test_providerNames() {
   }
 });
 
-add_task(async function test_cfr_notification_keyboard() {
-  // addRecommendation checks that scheme starts with http and host matches
-  const browser = gBrowser.selectedBrowser;
-  BrowserTestUtils.startLoadingURIString(browser, "http://example.com/");
-  await BrowserTestUtils.browserLoaded(browser, false, "http://example.com/");
-
-  const response = await trigger_cfr_panel(browser, "example.com");
-  Assert.ok(
-    response,
-    "Should return true if addRecommendation checks were successful"
-  );
-
-  // Open the panel with the keyboard.
-  // Toolbar buttons aren't always focusable; toolbar keyboard navigation
-  // makes them focusable on demand. Therefore, we must force focus.
-  const button = document.getElementById("contextual-feature-recommendation");
-  button.setAttribute("tabindex", "-1");
-  button.focus();
-  button.removeAttribute("tabindex");
-
-  let focused = BrowserTestUtils.waitForEvent(
-    PopupNotifications.panel,
-    "focus",
-    true
-  );
-  EventUtils.synthesizeKey(" ");
-  await focused;
-  Assert.ok(true, "Focus inside panel after button pressed");
-
-  let hidden = BrowserTestUtils.waitForEvent(
-    PopupNotifications.panel,
-    "popuphidden"
-  );
-  EventUtils.synthesizeKey("KEY_Escape");
-  await hidden;
-  Assert.ok(true, "Panel hidden after Escape pressed");
-
-  const showPanel = BrowserTestUtils.waitForEvent(
-    PopupNotifications.panel,
-    "popupshown"
-  );
-  // Need to dismiss the notification to clear the RecommendationMap
-  document.getElementById("contextual-feature-recommendation").click();
-  await showPanel;
-
-  const hidePanel = BrowserTestUtils.waitForEvent(
-    PopupNotifications.panel,
-    "popuphidden"
-  );
-  document
-    .getElementById("contextual-feature-recommendation-notification")
-    .button.click();
-  await hidePanel;
-  Services.fog.testResetFOG();
-});
-
 add_task(function test_updateCycleForProviders() {
   Services.prefs
     .getChildList("browser.newtabpage.activity-stream.asrouter.providers.")
diff --git a/browser/components/asrouter/tests/browser/browser_asrouter_keyboard_cfr.js b/browser/components/asrouter/tests/browser/browser_asrouter_keyboard_cfr.js
new file mode 100644
index 0000000000..c3dfc0b0bb
--- /dev/null
+++ b/browser/components/asrouter/tests/browser/browser_asrouter_keyboard_cfr.js
@@ -0,0 +1,162 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* eslint-disable @microsoft/sdl/no-insecure-url */
+function clearNotifications() {
+  for (let notification of PopupNotifications._currentNotifications) {
+    notification.remove();
+  }
+
+  // Clicking the primary action also removes the notification
+  Assert.equal(
+    PopupNotifications._currentNotifications.length,
+    0,
+    "Should have removed the notification"
+  );
+}
+
+add_setup(async function () {
+  // Store it in order to restore to the original value
+  const { _fetchLatestAddonVersion } = CFRPageActions;
+  // Prevent fetching the real addon url and making a network request
+  CFRPageActions._fetchLatestAddonVersion = () => "http://example.com";
+  Services.fog.testResetFOG();
+
+  registerCleanupFunction(() => {
+    CFRPageActions._fetchLatestAddonVersion = _fetchLatestAddonVersion;
+    clearNotifications();
+    CFRPageActions.clearRecommendations();
+  });
+});
+
+add_task(async function test_cfr_notification_keyboard() {
+  // addRecommendation checks that scheme starts with http and host matches
+  const browser = gBrowser.selectedBrowser;
+  BrowserTestUtils.startLoadingURIString(browser, "http://example.com/");
+  await BrowserTestUtils.browserLoaded(browser, false, "http://example.com/");
+
+  clearNotifications();
+
+  let recommendation = {
+    template: "cfr_doorhanger",
+    groups: ["mochitest-group"],
+    content: {
+      layout: "addon_recommendation",
+      category: "cfrAddons",
+      anchor_id: "page-action-buttons",
+      icon_class: "cfr-doorhanger-medium-icon",
+      skip_address_bar_notifier: false,
+      heading_text: "Sample Mochitest",
+      icon: "chrome://activity-stream/content/data/content/assets/glyph-webextension-16.svg",
+      icon_dark_theme:
+        "chrome://activity-stream/content/data/content/assets/glyph-webextension-16.svg",
+      info_icon: {
+        label: { attributes: { tooltiptext: "Why am I seeing this" } },
+        sumo_path: "extensionrecommendations",
+      },
+      addon: {
+        id: "addon-id",
+        title: "Addon name",
+        icon: "chrome://browser/skin/addons/addon-install-downloading.svg",
+        author: "Author name",
+        amo_url: "https://example.com",
+        rating: "4.5",
+        users: "1.1M",
+      },
+      text: "Mochitest",
+      buttons: {
+        primary: {
+          label: {
+            value: "OK",
+            attributes: { accesskey: "O" },
+          },
+          action: {
+            type: "CANCEL",
+            data: {},
+          },
+        },
+        secondary: [
+          {
+            label: {
+              value: "Cancel",
+              attributes: { accesskey: "C" },
+            },
+            action: {
+              type: "CANCEL",
+            },
+          },
+        ],
+      },
+    },
+  };
+
+  recommendation.content.notification_text = new String("Mochitest"); // eslint-disable-line
+  recommendation.content.notification_text.attributes = {
+    tooltiptext: "Mochitest tooltip",
+    "a11y-announcement": "Mochitest announcement",
+  };
+
+  const response = await CFRPageActions.addRecommendation(
+    gBrowser.selectedBrowser,
+    "example.com",
+    recommendation,
+    // Use the real AS dispatch method to trigger real notifications
+    ASRouter.dispatchCFRAction
+  );
+
+  Assert.ok(
+    response,
+    "Should return true if addRecommendation checks were successful"
+  );
+
+  // Open the panel with the keyboard.
+  // Toolbar buttons aren't always focusable; toolbar keyboard navigation
+  // makes them focusable on demand. Therefore, we must force focus.
+  const button = document.getElementById("contextual-feature-recommendation");
+  button.setAttribute("tabindex", "-1");
+
+  let buttonFocused = BrowserTestUtils.waitForEvent(button, "focus");
+  button.focus();
+  await buttonFocused;
+
+  Assert.ok(true, "Focus page action button");
+
+  let focused = BrowserTestUtils.waitForEvent(
+    PopupNotifications.panel,
+    "focus",
+    true
+  );
+
+  EventUtils.synthesizeKey(" ");
+  await focused;
+  Assert.ok(true, "Focus inside panel after button pressed");
+
+  button.removeAttribute("tabindex");
+
+  let hidden = BrowserTestUtils.waitForEvent(
+    PopupNotifications.panel,
+    "popuphidden"
+  );
+  EventUtils.synthesizeKey("KEY_Escape");
+  await hidden;
+  Assert.ok(true, "Panel hidden after Escape pressed");
+
+  const showPanel = BrowserTestUtils.waitForEvent(
+    PopupNotifications.panel,
+    "popupshown"
+  );
+  // Need to dismiss the notification to clear the RecommendationMap
+  document.getElementById("contextual-feature-recommendation").click();
+  await showPanel;
+
+  const hidePanel = BrowserTestUtils.waitForEvent(
+    PopupNotifications.panel,
+    "popuphidden"
+  );
+  document
+    .getElementById("contextual-feature-recommendation-notification")
+    .button.click();
+  await hidePanel;
+  Services.fog.testResetFOG();
+});
diff --git a/browser/components/asrouter/tests/browser/browser_asrouter_milestone_message_cfr.js b/browser/components/asrouter/tests/browser/browser_asrouter_milestone_message_cfr.js
new file mode 100644
index 0000000000..6585963d6f
--- /dev/null
+++ b/browser/components/asrouter/tests/browser/browser_asrouter_milestone_message_cfr.js
@@ -0,0 +1,78 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* eslint-disable @microsoft/sdl/no-insecure-url */
+function checkCFRTrackingProtectionMilestone(notification) {
+  Assert.ok(notification.hidden === false, "Panel should be visible");
+  Assert.ok(
+    notification.getAttribute("data-notification-category") === "short_message",
+    "Panel have correct data attribute"
+  );
+}
+
+function clearNotifications() {
+  for (let notification of PopupNotifications._currentNotifications) {
+    notification.remove();
+  }
+
+  // Clicking the primary action also removes the notification
+  Assert.equal(
+    PopupNotifications._currentNotifications.length,
+    0,
+    "Should have removed the notification"
+  );
+}
+
+add_task(
+  async function test_cfr_tracking_protection_milestone_notification_remove() {
+    await SpecialPowers.pushPrefEnv({
+      set: [
+        ["browser.contentblocking.cfr-milestone.milestone-achieved", 1000],
+        [
+          "browser.newtabpage.activity-stream.asrouter.providers.cfr",
+          `{"id":"cfr","enabled":true,"type":"local","localProvider":"CFRMessageProvider","updateCycleInMs":3600000}`,
+        ],
+      ],
+    });
+
+    // addRecommendation checks that scheme starts with http and host matches
+    let browser = gBrowser.selectedBrowser;
+    BrowserTestUtils.startLoadingURIString(browser, "http://example.com/");
+    await BrowserTestUtils.browserLoaded(browser, false, "http://example.com/");
+
+    const showPanel = BrowserTestUtils.waitForEvent(
+      PopupNotifications.panel,
+      "popupshown"
+    );
+
+    Services.obs.notifyObservers(
+      {
+        wrappedJSObject: {
+          event: "ContentBlockingMilestone",
+        },
+      },
+      "SiteProtection:ContentBlockingMilestone"
+    );
+
+    await showPanel;
+
+    const notification = document.getElementById(
+      "contextual-feature-recommendation-notification"
+    );
+
+    checkCFRTrackingProtectionMilestone(notification);
+
+    Assert.ok(notification.secondaryButton);
+    let hidePanel = BrowserTestUtils.waitForEvent(
+      PopupNotifications.panel,
+      "popuphidden"
+    );
+
+    notification.secondaryButton.click();
+    await hidePanel;
+    await SpecialPowers.popPrefEnv();
+    clearNotifications();
+    Services.fog.testResetFOG();
+  }
+);
diff --git a/browser/components/asrouter/tests/browser/browser_asrouter_momentspagehub.js b/browser/components/asrouter/tests/browser/browser_asrouter_momentspagehub.js
index f752d01116..aea702bb61 100644
--- a/browser/components/asrouter/tests/browser/browser_asrouter_momentspagehub.js
+++ b/browser/components/asrouter/tests/browser/browser_asrouter_momentspagehub.js
@@ -14,11 +14,11 @@ const { ASRouter } = ChromeUtils.importESModule(
 const HOMEPAGE_OVERRIDE_PREF = "browser.startup.homepage_override.once";
 
 add_task(async function test_with_rs_messages() {
-  // Force the WNPanel provider cache to 0 by modifying updateCycleInMs
+  // Force the cfr provider cache to 0 by modifying updateCycleInMs
   await SpecialPowers.pushPrefEnv({
     set: [
       [
-        "browser.newtabpage.activity-stream.asrouter.providers.whats-new-panel",
+        "browser.newtabpage.activity-stream.asrouter.providers.cfr",
         `{"id":"cfr","enabled":true,"type":"remote-settings","collection":"cfr","updateCycleInMs":0}`,
       ],
     ],
diff --git a/browser/components/asrouter/tests/unit/ASRouter.test.js b/browser/components/asrouter/tests/unit/ASRouter.test.js
index 7df1449a14..1f5899fce1 100644
--- a/browser/components/asrouter/tests/unit/ASRouter.test.js
+++ b/browser/components/asrouter/tests/unit/ASRouter.test.js
@@ -48,7 +48,6 @@ describe("ASRouter", () => {
   let fakeAttributionCode;
   let fakeTargetingContext;
   let FakeToolbarBadgeHub;
-  let FakeToolbarPanelHub;
   let FakeMomentsPageHub;
   let ASRouterTargeting;
   let screenImpressions;
@@ -151,7 +150,6 @@ describe("ASRouter", () => {
           cfr: "",
           "message-groups": "",
           "messaging-experiments": "",
-          "whats-new-panel": "",
         },
         totalBookmarksCount: {},
         firefoxVersion: 80,
@@ -159,7 +157,6 @@ describe("ASRouter", () => {
         needsUpdate: {},
         hasPinnedTabs: false,
         hasAccessedFxAPanel: false,
-        isWhatsNewPanelEnabled: true,
         userPrefs: {
           cfrFeatures: true,
           cfrAddons: true,
@@ -203,12 +200,6 @@ describe("ASRouter", () => {
       writeAttributionFile: () => Promise.resolve(),
       getCachedAttributionData: sinon.stub(),
     };
-    FakeToolbarPanelHub = {
-      init: sandbox.stub(),
-      uninit: sandbox.stub(),
-      forceShowMessage: sandbox.stub(),
-      enableToolbarButton: sandbox.stub(),
-    };
     FakeToolbarBadgeHub = {
       init: sandbox.stub(),
       uninit: sandbox.stub(),
@@ -252,7 +243,6 @@ describe("ASRouter", () => {
       PanelTestProvider,
       MacAttribution: { applicationPath: "" },
       ToolbarBadgeHub: FakeToolbarBadgeHub,
-      ToolbarPanelHub: FakeToolbarPanelHub,
       MomentsPageHub: FakeMomentsPageHub,
       KintoHttpClient: class {
         bucket() {
@@ -354,7 +344,6 @@ describe("ASRouter", () => {
       // ASRouter init called in `beforeEach` block above
 
       assert.calledOnce(FakeToolbarBadgeHub.init);
-      assert.calledOnce(FakeToolbarPanelHub.init);
       assert.calledOnce(FakeMomentsPageHub.init);
 
       assert.calledWithExactly(
@@ -370,15 +359,6 @@ describe("ASRouter", () => {
       );
 
       assert.calledWithExactly(
-        FakeToolbarPanelHub.init,
-        Router.waitForInitialized,
-        {
-          getMessages: Router.handleMessageRequest,
-          sendTelemetry: Router.sendTelemetry,
-        }
-      );
-
-      assert.calledWithExactly(
         FakeMomentsPageHub.init,
         Router.waitForInitialized,
         {
@@ -678,25 +658,10 @@ describe("ASRouter", () => {
       sandbox.stub(CFRPageActions, "addRecommendation");
       browser = {};
     });
-    it("should route whatsnew_panel_message message to the right hub", () => {
-      Router.routeCFRMessage(
-        { template: "whatsnew_panel_message" },
-        browser,
-        "",
-        true
-      );
-
-      assert.calledOnce(FakeToolbarPanelHub.forceShowMessage);
-      assert.notCalled(FakeToolbarBadgeHub.registerBadgeNotificationListener);
-      assert.notCalled(CFRPageActions.addRecommendation);
-      assert.notCalled(CFRPageActions.forceRecommendation);
-      assert.notCalled(FakeMomentsPageHub.executeAction);
-    });
     it("should route moments messages to the right hub", () => {
       Router.routeCFRMessage({ template: "update_action" }, browser, "", true);
 
       assert.calledOnce(FakeMomentsPageHub.executeAction);
-      assert.notCalled(FakeToolbarPanelHub.forceShowMessage);
       assert.notCalled(FakeToolbarBadgeHub.registerBadgeNotificationListener);
       assert.notCalled(CFRPageActions.addRecommendation);
       assert.notCalled(CFRPageActions.forceRecommendation);
@@ -705,7 +670,6 @@ describe("ASRouter", () => {
       Router.routeCFRMessage({ template: "toolbar_badge" }, browser);
 
       assert.calledOnce(FakeToolbarBadgeHub.registerBadgeNotificationListener);
-      assert.notCalled(FakeToolbarPanelHub.forceShowMessage);
       assert.notCalled(CFRPageActions.addRecommendation);
       assert.notCalled(CFRPageActions.forceRecommendation);
       assert.notCalled(FakeMomentsPageHub.executeAction);
@@ -721,7 +685,6 @@ describe("ASRouter", () => {
       assert.calledOnce(CFRPageActions.addRecommendation);
       assert.notCalled(CFRPageActions.forceRecommendation);
       assert.notCalled(FakeToolbarBadgeHub.registerBadgeNotificationListener);
-      assert.notCalled(FakeToolbarPanelHub.forceShowMessage);
       assert.notCalled(FakeMomentsPageHub.executeAction);
     });
     it("should route cfr_doorhanger message to the right hub force = false", () => {
@@ -733,7 +696,6 @@ describe("ASRouter", () => {
       );
 
       assert.calledOnce(CFRPageActions.addRecommendation);
-      assert.notCalled(FakeToolbarPanelHub.forceShowMessage);
       assert.notCalled(FakeToolbarBadgeHub.registerBadgeNotificationListener);
       assert.notCalled(CFRPageActions.forceRecommendation);
       assert.notCalled(FakeMomentsPageHub.executeAction);
@@ -742,7 +704,6 @@ describe("ASRouter", () => {
       Router.routeCFRMessage({ template: "cfr_doorhanger" }, browser, {}, true);
 
       assert.calledOnce(CFRPageActions.forceRecommendation);
-      assert.notCalled(FakeToolbarPanelHub.forceShowMessage);
       assert.notCalled(CFRPageActions.addRecommendation);
       assert.notCalled(FakeToolbarBadgeHub.registerBadgeNotificationListener);
       assert.notCalled(FakeMomentsPageHub.executeAction);
@@ -759,7 +720,6 @@ describe("ASRouter", () => {
       const { args } = CFRPageActions.addRecommendation.firstCall;
       // Host should be null
       assert.isNull(args[1]);
-      assert.notCalled(FakeToolbarPanelHub.forceShowMessage);
       assert.notCalled(FakeToolbarBadgeHub.registerBadgeNotificationListener);
       assert.notCalled(CFRPageActions.forceRecommendation);
       assert.notCalled(FakeMomentsPageHub.executeAction);
@@ -773,7 +733,6 @@ describe("ASRouter", () => {
       );
 
       assert.calledOnce(CFRPageActions.forceRecommendation);
-      assert.notCalled(FakeToolbarPanelHub.forceShowMessage);
       assert.notCalled(CFRPageActions.addRecommendation);
       assert.notCalled(FakeToolbarBadgeHub.registerBadgeNotificationListener);
       assert.notCalled(FakeMomentsPageHub.executeAction);
@@ -786,7 +745,6 @@ describe("ASRouter", () => {
         true
       );
 
-      assert.notCalled(FakeToolbarPanelHub.forceShowMessage);
       assert.notCalled(CFRPageActions.forceRecommendation);
       assert.notCalled(CFRPageActions.addRecommendation);
       assert.notCalled(FakeToolbarBadgeHub.registerBadgeNotificationListener);
@@ -961,7 +919,6 @@ describe("ASRouter", () => {
           type: "local",
           enabled: true,
           messages: [
-            "whatsnew_panel_message",
             "cfr_doorhanger",
             "toolbar_badge",
             "update_action",
@@ -1272,43 +1229,6 @@ describe("ASRouter", () => {
         Router.state.messageImpressions
       );
     });
-    it("should return all unblocked messages that match the template, trigger if returnAll=true", async () => {
-      const message1 = {
-        provider: "whats_new",
-        id: "1",
-        template: "whatsnew_panel_message",
-        trigger: { id: "whatsNewPanelOpened" },
-        groups: ["whats_new"],
-      };
-      const message2 = {
-        provider: "whats_new",
-        id: "2",
-        template: "whatsnew_panel_message",
-        trigger: { id: "whatsNewPanelOpened" },
-        groups: ["whats_new"],
-      };
-      const message3 = {
-        provider: "whats_new",
-        id: "3",
-        template: "badge",
-        groups: ["whats_new"],
-      };
-      ASRouterTargeting.findMatchingMessage.callsFake(() => [
-        message2,
-        message1,
-      ]);
-      await Router.setState({
-        messages: [message3, message2, message1],
-        providers: [{ id: "whats_new" }],
-      });
-      const result = await Router.handleMessageRequest({
-        template: "whatsnew_panel_message",
-        triggerId: "whatsNewPanelOpened",
-        returnAll: true,
-      });
-
-      assert.deepEqual(result, [message2, message1]);
-    });
     it("should forward trigger param info", async () => {
       const trigger = {
         triggerId: "foo",
@@ -1854,33 +1774,6 @@ describe("ASRouter", () => {
     });
   });
 
-  describe("#forceWNPanel", () => {
-    let browser = {
-      ownerGlobal: {
-        document: new Document(),
-        PanelUI: {
-          showSubView: sinon.stub(),
-          panel: {
-            setAttribute: sinon.stub(),
-          },
-        },
-      },
-    };
-    let fakePanel = {
-      setAttribute: sinon.stub(),
-    };
-    sinon
-      .stub(browser.ownerGlobal.document, "getElementById")
-      .returns(fakePanel);
-
-    it("should call enableToolbarButton", async () => {
-      await Router.forceWNPanel(browser);
-      assert.calledOnce(FakeToolbarPanelHub.enableToolbarButton);
-      assert.calledOnce(browser.ownerGlobal.PanelUI.showSubView);
-      assert.calledWith(fakePanel.setAttribute, "noautohide", true);
-    });
-  });
-
   describe("_triggerHandler", () => {
     it("should call #sendTriggerMessage with the correct trigger", () => {
       const getter = sandbox.stub();
diff --git a/browser/components/asrouter/tests/unit/ASRouterChild.test.js b/browser/components/asrouter/tests/unit/ASRouterChild.test.js
index b73e56d510..c6533e073d 100644
--- a/browser/components/asrouter/tests/unit/ASRouterChild.test.js
+++ b/browser/components/asrouter/tests/unit/ASRouterChild.test.js
@@ -1,6 +1,6 @@
 /*eslint max-nested-callbacks: ["error", 10]*/
 import { ASRouterChild } from "actors/ASRouterChild.sys.mjs";
-import { MESSAGE_TYPE_HASH as msg } from "modules/ActorConstants.sys.mjs";
+import { MESSAGE_TYPE_HASH as msg } from "modules/ActorConstants.mjs";
 
 describe("ASRouterChild", () => {
   let asRouterChild = null;
@@ -24,7 +24,6 @@ describe("ASRouterChild", () => {
         msg.DISABLE_PROVIDER,
         msg.ENABLE_PROVIDER,
         msg.EXPIRE_QUERY_CACHE,
-        msg.FORCE_WHATSNEW_PANEL,
         msg.IMPRESSION,
         msg.RESET_PROVIDER_PREF,
         msg.SET_PROVIDER_USER_PREF,
diff --git a/browser/components/asrouter/tests/unit/ASRouterParent.test.js b/browser/components/asrouter/tests/unit/ASRouterParent.test.js
index 0358b1261c..e65d7db825 100644
--- a/browser/components/asrouter/tests/unit/ASRouterParent.test.js
+++ b/browser/components/asrouter/tests/unit/ASRouterParent.test.js
@@ -1,5 +1,5 @@
 import { ASRouterParent } from "actors/ASRouterParent.sys.mjs";
-import { MESSAGE_TYPE_HASH as msg } from "modules/ActorConstants.sys.mjs";
+import { MESSAGE_TYPE_HASH as msg } from "modules/ActorConstants.mjs";
 
 describe("ASRouterParent", () => {
   let asRouterParent = null;
diff --git a/browser/components/asrouter/tests/unit/ASRouterParentProcessMessageHandler.test.js b/browser/components/asrouter/tests/unit/ASRouterParentProcessMessageHandler.test.js
index 7bfec3e099..6a965c5689 100644
--- a/browser/components/asrouter/tests/unit/ASRouterParentProcessMessageHandler.test.js
+++ b/browser/components/asrouter/tests/unit/ASRouterParentProcessMessageHandler.test.js
@@ -1,6 +1,6 @@
 import { ASRouterParentProcessMessageHandler } from "modules/ASRouterParentProcessMessageHandler.sys.mjs";
 import { _ASRouter } from "modules/ASRouter.sys.mjs";
-import { MESSAGE_TYPE_HASH as msg } from "modules/ActorConstants.sys.mjs";
+import { MESSAGE_TYPE_HASH as msg } from "modules/ActorConstants.mjs";
 
 describe("ASRouterParentProcessMessageHandler", () => {
   let handler = null;
@@ -14,8 +14,6 @@ describe("ASRouterParentProcessMessageHandler", () => {
       "addImpression",
       "evaluateExpression",
       "forceAttribution",
-      "forceWNPanel",
-      "closeWNPanel",
       "forcePBWindow",
       "resetGroupsState",
       "resetMessageState",
@@ -122,7 +120,6 @@ describe("ASRouterParentProcessMessageHandler", () => {
     [
       msg.AS_ROUTER_TELEMETRY_USER_EVENT,
       msg.TOOLBAR_BADGE_TELEMETRY,
-      msg.TOOLBAR_PANEL_TELEMETRY,
       msg.MOMENTS_PAGE_TELEMETRY,
       msg.DOORHANGER_TELEMETRY,
     ].forEach(type => {
@@ -309,28 +306,6 @@ describe("ASRouterParentProcessMessageHandler", () => {
         assert.calledOnce(config.router.forceAttribution);
       });
     });
-    describe("FORCE_WHATSNEW_PANEL action", () => {
-      it("default calls forceWNPanel", () => {
-        handler.handleMessage(
-          msg.FORCE_WHATSNEW_PANEL,
-          {},
-          { browser: { ownerGlobal: {} } }
-        );
-        assert.calledOnce(config.router.forceWNPanel);
-        assert.calledWith(config.router.forceWNPanel, { ownerGlobal: {} });
-      });
-    });
-    describe("CLOSE_WHATSNEW_PANEL action", () => {
-      it("default calls closeWNPanel", () => {
-        handler.handleMessage(
-          msg.CLOSE_WHATSNEW_PANEL,
-          {},
-          { browser: { ownerGlobal: {} } }
-        );
-        assert.calledOnce(config.router.closeWNPanel);
-        assert.calledWith(config.router.closeWNPanel, { ownerGlobal: {} });
-      });
-    });
     describe("FORCE_PRIVATE_BROWSING_WINDOW action", () => {
       it("default calls forcePBWindow", () => {
         handler.handleMessage(
diff --git a/browser/components/asrouter/tests/unit/ToolbarBadgeHub.test.js b/browser/components/asrouter/tests/unit/ToolbarBadgeHub.test.js
index 3e91b657bc..cfeac77025 100644
--- a/browser/components/asrouter/tests/unit/ToolbarBadgeHub.test.js
+++ b/browser/components/asrouter/tests/unit/ToolbarBadgeHub.test.js
@@ -1,10 +1,6 @@
 import { _ToolbarBadgeHub } from "modules/ToolbarBadgeHub.sys.mjs";
 import { GlobalOverrider } from "test/unit/utils";
 import { OnboardingMessageProvider } from "modules/OnboardingMessageProvider.sys.mjs";
-import {
-  _ToolbarPanelHub,
-  ToolbarPanelHub,
-} from "modules/ToolbarPanelHub.sys.mjs";
 
 describe("ToolbarBadgeHub", () => {
   let sandbox;
@@ -13,7 +9,6 @@ describe("ToolbarBadgeHub", () => {
   let fakeSendTelemetry;
   let isBrowserPrivateStub;
   let fxaMessage;
-  let whatsnewMessage;
   let fakeElement;
   let globals;
   let everyWindowStub;
@@ -36,28 +31,6 @@ describe("ToolbarBadgeHub", () => {
     const onboardingMsgs =
       await OnboardingMessageProvider.getUntranslatedMessages();
     fxaMessage = onboardingMsgs.find(({ id }) => id === "FXA_ACCOUNTS_BADGE");
-    whatsnewMessage = {
-      id: `WHATS_NEW_BADGE_71`,
-      template: "toolbar_badge",
-      content: {
-        delay: 1000,
-        target: "whats-new-menu-button",
-        action: { id: "show-whatsnew-button" },
-        badgeDescription: { string_id: "cfr-badge-reader-label-newfeature" },
-      },
-      priority: 1,
-      trigger: { id: "toolbarBadgeUpdate" },
-      frequency: {
-        // Makes it so that we track impressions for this message while at the
-        // same time it can have unlimited impressions
-        lifetime: Infinity,
-      },
-      // Never saw this message or saw it in the past 4 days or more recent
-      targeting: `isWhatsNewPanelEnabled &&
-      (!messageImpressions['WHATS_NEW_BADGE_71'] ||
-        (messageImpressions['WHATS_NEW_BADGE_71']|length >= 1 &&
-          currentDate|date - messageImpressions['WHATS_NEW_BADGE_71'][0] <= 4 * 24 * 3600 * 1000))`,
-    };
     fakeElement = {
       classList: {
         add: sandbox.stub(),
@@ -93,7 +66,6 @@ describe("ToolbarBadgeHub", () => {
     setStringPrefStub = sandbox.stub();
     requestIdleCallbackStub = sandbox.stub().callsFake(fn => fn());
     globals.set({
-      ToolbarPanelHub,
       requestIdleCallback: requestIdleCallbackStub,
       EveryWindow: everyWindowStub,
       PrivateBrowsingUtils: { isBrowserPrivate: isBrowserPrivateStub },
@@ -139,16 +111,6 @@ describe("ToolbarBadgeHub", () => {
 
       assert.calledTwice(instance.messageRequest);
     });
-    it("should add a pref observer", async () => {
-      await instance.init(sandbox.stub().resolves(), {});
-
-      assert.calledOnce(addObserverStub);
-      assert.calledWithExactly(
-        addObserverStub,
-        instance.prefs.WHATSNEW_TOOLBAR_PANEL,
-        instance
-      );
-    });
   });
   describe("#uninit", () => {
     beforeEach(async () => {
@@ -164,16 +126,6 @@ describe("ToolbarBadgeHub", () => {
       assert.calledOnce(clearTimeoutStub);
       assert.calledWithExactly(clearTimeoutStub, 2);
     });
-    it("should remove the pref observer", () => {
-      instance.uninit();
-
-      assert.calledOnce(removeObserverStub);
-      assert.calledWithExactly(
-        removeObserverStub,
-        instance.prefs.WHATSNEW_TOOLBAR_PANEL,
-        instance
-      );
-    });
   });
   describe("messageRequest", () => {
     let handleMessageRequestStub;
@@ -293,66 +245,6 @@ describe("ToolbarBadgeHub", () => {
         instance.removeAllNotifications
       );
     });
-    it("should execute actions if they exist", () => {
-      sandbox.stub(instance, "executeAction");
-      instance.addToolbarNotification(target, whatsnewMessage);
-
-      assert.calledOnce(instance.executeAction);
-      assert.calledWithExactly(instance.executeAction, {
-        ...whatsnewMessage.content.action,
-        message_id: whatsnewMessage.id,
-      });
-    });
-    it("should create a description element", () => {
-      sandbox.stub(instance, "executeAction");
-      instance.addToolbarNotification(target, whatsnewMessage);
-
-      assert.calledOnce(fakeDocument.createElement);
-      assert.calledWithExactly(fakeDocument.createElement, "span");
-    });
-    it("should set description id to element and to button", () => {
-      sandbox.stub(instance, "executeAction");
-      instance.addToolbarNotification(target, whatsnewMessage);
-
-      assert.calledWithExactly(
-        fakeElement.setAttribute,
-        "id",
-        "toolbarbutton-notification-description"
-      );
-      assert.calledWithExactly(
-        fakeElement.setAttribute,
-        "aria-labelledby",
-        `toolbarbutton-notification-description ${whatsnewMessage.content.target}`
-      );
-    });
-    it("should attach fluent id to description", () => {
-      sandbox.stub(instance, "executeAction");
-      instance.addToolbarNotification(target, whatsnewMessage);
-
-      assert.calledOnce(fakeDocument.l10n.setAttributes);
-      assert.calledWithExactly(
-        fakeDocument.l10n.setAttributes,
-        fakeElement,
-        whatsnewMessage.content.badgeDescription.string_id
-      );
-    });
-    it("should add an impression for the message", () => {
-      instance.addToolbarNotification(target, whatsnewMessage);
-
-      assert.calledOnce(instance._addImpression);
-      assert.calledWithExactly(instance._addImpression, whatsnewMessage);
-    });
-    it("should send an impression ping", async () => {
-      sandbox.stub(instance, "sendUserEventTelemetry");
-      instance.addToolbarNotification(target, whatsnewMessage);
-
-      assert.calledOnce(instance.sendUserEventTelemetry);
-      assert.calledWithExactly(
-        instance.sendUserEventTelemetry,
-        "IMPRESSION",
-        whatsnewMessage
-      );
-    });
   });
   describe("registerBadgeNotificationListener", () => {
     let msg_no_delay;
@@ -410,44 +302,6 @@ describe("ToolbarBadgeHub", () => {
       assert.calledOnce(everyWindowStub.unregisterCallback);
       assert.calledWithExactly(everyWindowStub.unregisterCallback, instance.id);
     });
-    it("should only call executeAction for 'update_action' messages", () => {
-      const stub = sandbox.stub(instance, "executeAction");
-      const updateActionMsg = { ...msg_no_delay, template: "update_action" };
-
-      instance.registerBadgeNotificationListener(updateActionMsg);
-
-      assert.notCalled(everyWindowStub.registerCallback);
-      assert.calledOnce(stub);
-    });
-  });
-  describe("executeAction", () => {
-    let blockMessageByIdStub;
-    beforeEach(async () => {
-      blockMessageByIdStub = sandbox.stub();
-      await instance.init(sandbox.stub().resolves(), {
-        blockMessageById: blockMessageByIdStub,
-      });
-    });
-    it("should call ToolbarPanelHub.enableToolbarButton", () => {
-      const stub = sandbox.stub(
-        _ToolbarPanelHub.prototype,
-        "enableToolbarButton"
-      );
-
-      instance.executeAction({ id: "show-whatsnew-button" });
-
-      assert.calledOnce(stub);
-    });
-    it("should call ToolbarPanelHub.enableAppmenuButton", () => {
-      const stub = sandbox.stub(
-        _ToolbarPanelHub.prototype,
-        "enableAppmenuButton"
-      );
-
-      instance.executeAction({ id: "show-whatsnew-button" });
-
-      assert.calledOnce(stub);
-    });
   });
   describe("removeToolbarNotification", () => {
     it("should remove the notification", () => {
@@ -629,24 +483,4 @@ describe("ToolbarBadgeHub", () => {
       assert.propertyVal(ping.data, "event", "CLICK");
     });
   });
-  describe("#observe", () => {
-    it("should make a message request when the whats new pref is changed", () => {
-      sandbox.stub(instance, "messageRequest");
-
-      instance.observe("", "", instance.prefs.WHATSNEW_TOOLBAR_PANEL);
-
-      assert.calledOnce(instance.messageRequest);
-      assert.calledWithExactly(instance.messageRequest, {
-        template: "toolbar_badge",
-        triggerId: "toolbarBadgeUpdate",
-      });
-    });
-    it("should not react to other pref changes", () => {
-      sandbox.stub(instance, "messageRequest");
-
-      instance.observe("", "", "foo");
-
-      assert.notCalled(instance.messageRequest);
-    });
-  });
 });
diff --git a/browser/components/asrouter/tests/unit/ToolbarPanelHub.test.js b/browser/components/asrouter/tests/unit/ToolbarPanelHub.test.js
deleted file mode 100644
index 1755f62308..0000000000
--- a/browser/components/asrouter/tests/unit/ToolbarPanelHub.test.js
+++ /dev/null
@@ -1,760 +0,0 @@
-import { _ToolbarPanelHub } from "modules/ToolbarPanelHub.sys.mjs";
-import { GlobalOverrider } from "test/unit/utils";
-import { PanelTestProvider } from "modules/PanelTestProvider.sys.mjs";
-
-describe("ToolbarPanelHub", () => {
-  let globals;
-  let sandbox;
-  let instance;
-  let everyWindowStub;
-  let fakeDocument;
-  let fakeWindow;
-  let fakeElementById;
-  let fakeElementByTagName;
-  let createdCustomElements = [];
-  let eventListeners = {};
-  let addObserverStub;
-  let removeObserverStub;
-  let getBoolPrefStub;
-  let setBoolPrefStub;
-  let waitForInitializedStub;
-  let isBrowserPrivateStub;
-  let fakeSendTelemetry;
-  let getEarliestRecordedDateStub;
-  let getEventsByDateRangeStub;
-  let defaultSearchStub;
-  let scriptloaderStub;
-  let fakeRemoteL10n;
-  let getViewNodeStub;
-
-  beforeEach(async () => {
-    sandbox = sinon.createSandbox();
-    globals = new GlobalOverrider();
-    instance = new _ToolbarPanelHub();
-    waitForInitializedStub = sandbox.stub().resolves();
-    fakeElementById = {
-      setAttribute: sandbox.stub(),
-      removeAttribute: sandbox.stub(),
-      querySelector: sandbox.stub().returns(null),
-      querySelectorAll: sandbox.stub().returns([]),
-      appendChild: sandbox.stub(),
-      addEventListener: sandbox.stub(),
-      hasAttribute: sandbox.stub(),
-      toggleAttribute: sandbox.stub(),
-      remove: sandbox.stub(),
-      removeChild: sandbox.stub(),
-    };
-    fakeElementByTagName = {
-      setAttribute: sandbox.stub(),
-      removeAttribute: sandbox.stub(),
-      querySelector: sandbox.stub().returns(null),
-      querySelectorAll: sandbox.stub().returns([]),
-      appendChild: sandbox.stub(),
-      addEventListener: sandbox.stub(),
-      hasAttribute: sandbox.stub(),
-      toggleAttribute: sandbox.stub(),
-      remove: sandbox.stub(),
-      removeChild: sandbox.stub(),
-    };
-    fakeDocument = {
-      getElementById: sandbox.stub().returns(fakeElementById),
-      getElementsByTagName: sandbox.stub().returns(fakeElementByTagName),
-      querySelector: sandbox.stub().returns({}),
-      createElement: tagName => {
-        const element = {
-          tagName,
-          classList: {},
-          addEventListener: (ev, fn) => {
-            eventListeners[ev] = fn;
-          },
-          appendChild: sandbox.stub(),
-          setAttribute: sandbox.stub(),
-          textContent: "",
-        };
-        element.classList.add = sandbox.stub();
-        element.classList.includes = className =>
-          element.classList.add.firstCall.args[0] === className;
-        createdCustomElements.push(element);
-        return element;
-      },
-      l10n: {
-        translateElements: sandbox.stub(),
-        translateFragment: sandbox.stub(),
-        formatMessages: sandbox.stub().resolves([{}]),
-        setAttributes: sandbox.stub(),
-      },
-    };
-    fakeWindow = {
-      // eslint-disable-next-line object-shorthand
-      DocumentFragment: function () {
-        return fakeElementById;
-      },
-      document: fakeDocument,
-      browser: {
-        ownerDocument: fakeDocument,
-      },
-      MozXULElement: { insertFTLIfNeeded: sandbox.stub() },
-      ownerGlobal: {
-        openLinkIn: sandbox.stub(),
-        gBrowser: "gBrowser",
-      },
-      PanelUI: {
-        panel: fakeElementById,
-        whatsNewPanel: fakeElementById,
-      },
-      customElements: { get: sandbox.stub() },
-    };
-    everyWindowStub = {
-      registerCallback: sandbox.stub(),
-      unregisterCallback: sandbox.stub(),
-    };
-    scriptloaderStub = { loadSubScript: sandbox.stub() };
-    addObserverStub = sandbox.stub();
-    removeObserverStub = sandbox.stub();
-    getBoolPrefStub = sandbox.stub();
-    setBoolPrefStub = sandbox.stub();
-    fakeSendTelemetry = sandbox.stub();
-    isBrowserPrivateStub = sandbox.stub();
-    getEarliestRecordedDateStub = sandbox.stub().returns(
-      // A random date that's not the current timestamp
-      new Date() - 500
-    );
-    getEventsByDateRangeStub = sandbox.stub().returns([]);
-    getViewNodeStub = sandbox.stub().returns(fakeElementById);
-    defaultSearchStub = { defaultEngine: { name: "DDG" } };
-    fakeRemoteL10n = {
-      l10n: {},
-      reloadL10n: sandbox.stub(),
-      createElement: sandbox
-        .stub()
-        .callsFake((doc, el) => fakeDocument.createElement(el)),
-    };
-    globals.set({
-      EveryWindow: everyWindowStub,
-      Services: {
-        ...Services,
-        prefs: {
-          addObserver: addObserverStub,
-          removeObserver: removeObserverStub,
-          getBoolPref: getBoolPrefStub,
-          setBoolPref: setBoolPrefStub,
-        },
-        search: defaultSearchStub,
-        scriptloader: scriptloaderStub,
-      },
-      PrivateBrowsingUtils: {
-        isBrowserPrivate: isBrowserPrivateStub,
-      },
-      TrackingDBService: {
-        getEarliestRecordedDate: getEarliestRecordedDateStub,
-        getEventsByDateRange: getEventsByDateRangeStub,
-      },
-      SpecialMessageActions: {
-        handleAction: sandbox.stub(),
-      },
-      RemoteL10n: fakeRemoteL10n,
-      PanelMultiView: {
-        getViewNode: getViewNodeStub,
-      },
-    });
-  });
-  afterEach(() => {
-    instance.uninit();
-    sandbox.restore();
-    globals.restore();
-    eventListeners = {};
-    createdCustomElements = [];
-  });
-  it("should create an instance", () => {
-    assert.ok(instance);
-  });
-  it("should enableAppmenuButton() on init() just once", async () => {
-    instance.enableAppmenuButton = sandbox.stub();
-
-    await instance.init(waitForInitializedStub, { getMessages: () => {} });
-    await instance.init(waitForInitializedStub, { getMessages: () => {} });
-
-    assert.calledOnce(instance.enableAppmenuButton);
-
-    instance.uninit();
-
-    await instance.init(waitForInitializedStub, { getMessages: () => {} });
-
-    assert.calledTwice(instance.enableAppmenuButton);
-  });
-  it("should unregisterCallback on uninit()", () => {
-    instance.uninit();
-    assert.calledTwice(everyWindowStub.unregisterCallback);
-  });
-  describe("#maybeLoadCustomElement", () => {
-    it("should not load customElements a second time", () => {
-      instance.maybeLoadCustomElement({ customElements: new Map() });
-      instance.maybeLoadCustomElement({
-        customElements: new Map([["remote-text", true]]),
-      });
-
-      assert.calledOnce(scriptloaderStub.loadSubScript);
-    });
-  });
-  describe("#toggleWhatsNewPref", () => {
-    it("should call Services.prefs.setBoolPref() with the opposite value", () => {
-      let checkbox = {};
-      let event = { target: checkbox };
-      // checkbox starts false
-      checkbox.checked = false;
-
-      // toggling the checkbox to set the value to true;
-      // Preferences.set() gets called before the checkbox changes,
-      // so we have to call it with the opposite value.
-      instance.toggleWhatsNewPref(event);
-
-      assert.calledOnce(setBoolPrefStub);
-      assert.calledWith(
-        setBoolPrefStub,
-        "browser.messaging-system.whatsNewPanel.enabled",
-        !checkbox.checked
-      );
-    });
-    it("should report telemetry with the opposite value", () => {
-      let sendUserEventTelemetryStub = sandbox.stub(
-        instance,
-        "sendUserEventTelemetry"
-      );
-      let event = {
-        target: { checked: true, ownerGlobal: fakeWindow },
-      };
-
-      instance.toggleWhatsNewPref(event);
-
-      assert.calledOnce(sendUserEventTelemetryStub);
-      const { args } = sendUserEventTelemetryStub.firstCall;
-      assert.equal(args[1], "WNP_PREF_TOGGLE");
-      assert.propertyVal(args[3].value, "prefValue", false);
-    });
-  });
-  describe("#enableAppmenuButton", () => {
-    it("should registerCallback on enableAppmenuButton() if there are messages", async () => {
-      await instance.init(waitForInitializedStub, {
-        getMessages: sandbox.stub().resolves([{}, {}]),
-      });
-      // init calls `enableAppmenuButton`
-      everyWindowStub.registerCallback.resetHistory();
-
-      await instance.enableAppmenuButton();
-
-      assert.calledOnce(everyWindowStub.registerCallback);
-      assert.calledWithExactly(
-        everyWindowStub.registerCallback,
-        "appMenu-whatsnew-button",
-        sinon.match.func,
-        sinon.match.func
-      );
-    });
-    it("should not registerCallback on enableAppmenuButton() if there are no messages", async () => {
-      instance.init(waitForInitializedStub, {
-        getMessages: sandbox.stub().resolves([]),
-      });
-      // init calls `enableAppmenuButton`
-      everyWindowStub.registerCallback.resetHistory();
-
-      await instance.enableAppmenuButton();
-
-      assert.notCalled(everyWindowStub.registerCallback);
-    });
-  });
-  describe("#disableAppmenuButton", () => {
-    it("should call the unregisterCallback", () => {
-      assert.notCalled(everyWindowStub.unregisterCallback);
-
-      instance.disableAppmenuButton();
-
-      assert.calledOnce(everyWindowStub.unregisterCallback);
-      assert.calledWithExactly(
-        everyWindowStub.unregisterCallback,
-        "appMenu-whatsnew-button"
-      );
-    });
-  });
-  describe("#enableToolbarButton", () => {
-    it("should registerCallback on enableToolbarButton if messages.length", async () => {
-      await instance.init(waitForInitializedStub, {
-        getMessages: sandbox.stub().resolves([{}, {}]),
-      });
-      // init calls `enableAppmenuButton`
-      everyWindowStub.registerCallback.resetHistory();
-
-      await instance.enableToolbarButton();
-
-      assert.calledOnce(everyWindowStub.registerCallback);
-      assert.calledWithExactly(
-        everyWindowStub.registerCallback,
-        "whats-new-menu-button",
-        sinon.match.func,
-        sinon.match.func
-      );
-    });
-    it("should not registerCallback on enableToolbarButton if no messages", async () => {
-      await instance.init(waitForInitializedStub, {
-        getMessages: sandbox.stub().resolves([]),
-      });
-
-      await instance.enableToolbarButton();
-
-      assert.notCalled(everyWindowStub.registerCallback);
-    });
-  });
-  describe("Show/Hide functions", () => {
-    it("should unhide appmenu button on _showAppmenuButton()", async () => {
-      await instance._showAppmenuButton(fakeWindow);
-
-      assert.equal(fakeElementById.hidden, false);
-    });
-    it("should hide appmenu button on _hideAppmenuButton()", () => {
-      instance._hideAppmenuButton(fakeWindow);
-      assert.equal(fakeElementById.hidden, true);
-    });
-    it("should not do anything if the window is closed", () => {
-      instance._hideAppmenuButton(fakeWindow, true);
-      assert.notCalled(global.PanelMultiView.getViewNode);
-    });
-    it("should not throw if the element does not exist", () => {
-      let fn = instance._hideAppmenuButton.bind(null, {
-        browser: { ownerDocument: {} },
-      });
-      getViewNodeStub.returns(undefined);
-      assert.doesNotThrow(fn);
-    });
-    it("should unhide toolbar button on _showToolbarButton()", async () => {
-      await instance._showToolbarButton(fakeWindow);
-
-      assert.equal(fakeElementById.hidden, false);
-    });
-    it("should hide toolbar button on _hideToolbarButton()", () => {
-      instance._hideToolbarButton(fakeWindow);
-      assert.equal(fakeElementById.hidden, true);
-    });
-  });
-  describe("#renderMessages", () => {
-    let getMessagesStub;
-    beforeEach(() => {
-      getMessagesStub = sandbox.stub();
-      instance.init(waitForInitializedStub, {
-        getMessages: getMessagesStub,
-        sendTelemetry: fakeSendTelemetry,
-      });
-    });
-    it("should have correct state", async () => {
-      const messages = (await PanelTestProvider.getMessages()).filter(
-        m => m.template === "whatsnew_panel_message"
-      );
-
-      getMessagesStub.returns(messages);
-      const ev1 = sandbox.stub();
-      ev1.withArgs("type").returns(1); // tracker
-      ev1.withArgs("count").returns(4);
-      const ev2 = sandbox.stub();
-      ev2.withArgs("type").returns(4); // fingerprinter
-      ev2.withArgs("count").returns(3);
-      getEventsByDateRangeStub.returns([
-        { getResultByName: ev1 },
-        { getResultByName: ev2 },
-      ]);
-
-      await instance.renderMessages(fakeWindow, fakeDocument, "container-id");
-
-      assert.propertyVal(instance.state.contentArguments, "trackerCount", 4);
-      assert.propertyVal(
-        instance.state.contentArguments,
-        "fingerprinterCount",
-        3
-      );
-    });
-    it("should render messages to the panel on renderMessages()", async () => {
-      const messages = (await PanelTestProvider.getMessages()).filter(
-        m => m.template === "whatsnew_panel_message"
-      );
-      messages[0].content.link_text = { string_id: "link_text_id" };
-
-      getMessagesStub.returns(messages);
-      const ev1 = sandbox.stub();
-      ev1.withArgs("type").returns(1); // tracker
-      ev1.withArgs("count").returns(4);
-      const ev2 = sandbox.stub();
-      ev2.withArgs("type").returns(4); // fingerprinter
-      ev2.withArgs("count").returns(3);
-      getEventsByDateRangeStub.returns([
-        { getResultByName: ev1 },
-        { getResultByName: ev2 },
-      ]);
-
-      await instance.renderMessages(fakeWindow, fakeDocument, "container-id");
-
-      for (let message of messages) {
-        assert.ok(
-          fakeRemoteL10n.createElement.args.find(
-            ([, , args]) => args && args.classList === "whatsNew-message-title"
-          )
-        );
-        if (message.content.layout === "tracking-protections") {
-          assert.ok(
-            fakeRemoteL10n.createElement.args.find(
-              ([, , args]) =>
-                args && args.classList === "whatsNew-message-subtitle"
-            )
-          );
-        }
-        if (message.id === "WHATS_NEW_FINGERPRINTER_COUNTER_72") {
-          assert.ok(
-            fakeRemoteL10n.createElement.args.find(
-              ([, el, args]) => el === "h2" && args.content === 3
-            )
-          );
-        }
-        assert.ok(
-          fakeRemoteL10n.createElement.args.find(
-            ([, , args]) =>
-              args && args.classList === "whatsNew-message-content"
-          )
-        );
-      }
-      // Call the click handler to make coverage happy.
-      eventListeners.mouseup();
-      assert.calledOnce(global.SpecialMessageActions.handleAction);
-    });
-    it("should clear previous messages on 2nd renderMessages()", async () => {
-      const messages = (await PanelTestProvider.getMessages()).filter(
-        m => m.template === "whatsnew_panel_message"
-      );
-      const removeStub = sandbox.stub();
-      fakeElementById.querySelectorAll.onCall(0).returns([]);
-      fakeElementById.querySelectorAll
-        .onCall(1)
-        .returns([{ remove: removeStub }, { remove: removeStub }]);
-
-      getMessagesStub.returns(messages);
-
-      await instance.renderMessages(fakeWindow, fakeDocument, "container-id");
-      await instance.renderMessages(fakeWindow, fakeDocument, "container-id");
-
-      assert.calledTwice(removeStub);
-    });
-    it("should sort based on order field value", async () => {
-      const messages = (await PanelTestProvider.getMessages()).filter(
-        m =>
-          m.template === "whatsnew_panel_message" &&
-          m.content.published_date === 1560969794394
-      );
-
-      messages.forEach(m => (m.content.title = m.order));
-
-      getMessagesStub.returns(messages);
-
-      await instance.renderMessages(fakeWindow, fakeDocument, "container-id");
-
-      // Select the title elements that are supposed to be set to the same
-      // value as the `order` field of the message
-      const titleEls = fakeRemoteL10n.createElement.args
-        .filter(
-          ([, , args]) => args && args.classList === "whatsNew-message-title"
-        )
-        .map(([, , args]) => args.content);
-      assert.deepEqual(titleEls, [1, 2, 3]);
-    });
-    it("should accept string for image attributes", async () => {
-      const messages = (await PanelTestProvider.getMessages()).filter(
-        m => m.id === "WHATS_NEW_70_1"
-      );
-      getMessagesStub.returns(messages);
-
-      await instance.renderMessages(fakeWindow, fakeDocument, "container-id");
-
-      const imageEl = createdCustomElements.find(el => el.tagName === "img");
-      assert.calledOnce(imageEl.setAttribute);
-      assert.calledWithExactly(
-        imageEl.setAttribute,
-        "alt",
-        "Firefox Send Logo"
-      );
-    });
-    it("should set state values as data-attribute", async () => {
-      const message = (await PanelTestProvider.getMessages()).find(
-        m => m.template === "whatsnew_panel_message"
-      );
-      getMessagesStub.returns([message]);
-      instance.state.contentArguments = { foo: "foo", bar: "bar" };
-
-      await instance.renderMessages(fakeWindow, fakeDocument, "container-id");
-
-      const [, , args] = fakeRemoteL10n.createElement.args.find(
-        ([, , elArgs]) => elArgs && elArgs.attributes
-      );
-      assert.ok(args);
-      // Currently this.state.contentArguments has 8 different entries
-      assert.lengthOf(Object.keys(args.attributes), 8);
-      assert.equal(
-        args.attributes.searchEngineName,
-        defaultSearchStub.defaultEngine.name
-      );
-    });
-    it("should only render unique dates (no duplicates)", async () => {
-      const messages = (await PanelTestProvider.getMessages()).filter(
-        m => m.template === "whatsnew_panel_message"
-      );
-      const uniqueDates = [
-        ...new Set(messages.map(m => m.content.published_date)),
-      ];
-      getMessagesStub.returns(messages);
-
-      await instance.renderMessages(fakeWindow, fakeDocument, "container-id");
-
-      const dateElements = fakeRemoteL10n.createElement.args.filter(
-        ([, el, args]) =>
-          el === "p" && args.classList === "whatsNew-message-date"
-      );
-      assert.lengthOf(dateElements, uniqueDates.length);
-    });
-    it("should listen for panelhidden and remove the toolbar button", async () => {
-      getMessagesStub.returns([]);
-      fakeDocument.getElementById
-        .withArgs("customizationui-widget-panel")
-        .returns(null);
-
-      await instance.renderMessages(fakeWindow, fakeDocument, "container-id");
-
-      assert.notCalled(fakeElementById.addEventListener);
-    });
-    it("should attach doCommand cbs that handle user actions", async () => {
-      const messages = (await PanelTestProvider.getMessages()).filter(
-        m => m.template === "whatsnew_panel_message"
-      );
-      getMessagesStub.returns(messages);
-
-      await instance.renderMessages(fakeWindow, fakeDocument, "container-id");
-
-      const messageEl = createdCustomElements.find(
-        el =>
-          el.tagName === "div" && el.classList.includes("whatsNew-message-body")
-      );
-      const anchorEl = createdCustomElements.find(el => el.tagName === "a");
-
-      assert.notCalled(global.SpecialMessageActions.handleAction);
-
-      messageEl.doCommand();
-      anchorEl.doCommand();
-
-      assert.calledTwice(global.SpecialMessageActions.handleAction);
-    });
-    it("should listen for panelhidden and remove the toolbar button", async () => {
-      getMessagesStub.returns([]);
-
-      await instance.renderMessages(fakeWindow, fakeDocument, "container-id");
-
-      assert.calledOnce(fakeElementById.addEventListener);
-      assert.calledWithExactly(
-        fakeElementById.addEventListener,
-        "popuphidden",
-        sinon.match.func,
-        {
-          once: true,
-        }
-      );
-      const [, cb] = fakeElementById.addEventListener.firstCall.args;
-
-      assert.notCalled(everyWindowStub.unregisterCallback);
-
-      cb();
-
-      assert.calledOnce(everyWindowStub.unregisterCallback);
-      assert.calledWithExactly(
-        everyWindowStub.unregisterCallback,
-        "whats-new-menu-button"
-      );
-    });
-    describe("#IMPRESSION", () => {
-      it("should dispatch a IMPRESSION for messages", async () => {
-        // means panel is triggered from the toolbar button
-        fakeElementById.hasAttribute.returns(true);
-        const messages = (await PanelTestProvider.getMessages()).filter(
-          m => m.template === "whatsnew_panel_message"
-        );
-        getMessagesStub.returns(messages);
-        const spy = sandbox.spy(instance, "sendUserEventTelemetry");
-
-        await instance.renderMessages(fakeWindow, fakeDocument, "container-id");
-
-        assert.calledOnce(spy);
-        assert.calledOnce(fakeSendTelemetry);
-        assert.propertyVal(
-          spy.firstCall.args[2],
-          "id",
-          messages
-            .map(({ id }) => id)
-            .sort()
-            .join(",")
-        );
-      });
-      it("should dispatch a CLICK for clicking a message", async () => {
-        // means panel is triggered from the toolbar button
-        fakeElementById.hasAttribute.returns(true);
-        // Force to render the message
-        fakeElementById.querySelector.returns(null);
-        const messages = (await PanelTestProvider.getMessages()).filter(
-          m => m.template === "whatsnew_panel_message"
-        );
-        getMessagesStub.returns([messages[0]]);
-        const spy = sandbox.spy(instance, "sendUserEventTelemetry");
-
-        await instance.renderMessages(fakeWindow, fakeDocument, "container-id");
-
-        assert.calledOnce(spy);
-        assert.calledOnce(fakeSendTelemetry);
-
-        spy.resetHistory();
-
-        // Message click event listener cb
-        eventListeners.mouseup();
-
-        assert.calledOnce(spy);
-        assert.calledWithExactly(spy, fakeWindow, "CLICK", messages[0]);
-      });
-      it("should dispatch a IMPRESSION with toolbar_dropdown", async () => {
-        // means panel is triggered from the toolbar button
-        fakeElementById.hasAttribute.returns(true);
-        const messages = (await PanelTestProvider.getMessages()).filter(
-          m => m.template === "whatsnew_panel_message"
-        );
-        getMessagesStub.resolves(messages);
-        const spy = sandbox.spy(instance, "sendUserEventTelemetry");
-        const panelPingId = messages
-          .map(({ id }) => id)
-          .sort()
-          .join(",");
-
-        await instance.renderMessages(fakeWindow, fakeDocument, "container-id");
-
-        assert.calledOnce(spy);
-        assert.calledWithExactly(
-          spy,
-          fakeWindow,
-          "IMPRESSION",
-          {
-            id: panelPingId,
-          },
-          {
-            value: {
-              view: "toolbar_dropdown",
-            },
-          }
-        );
-        assert.calledOnce(fakeSendTelemetry);
-        const {
-          args: [dispatchPayload],
-        } = fakeSendTelemetry.lastCall;
-        assert.propertyVal(dispatchPayload, "type", "TOOLBAR_PANEL_TELEMETRY");
-        assert.propertyVal(dispatchPayload.data, "message_id", panelPingId);
-        assert.deepEqual(dispatchPayload.data.event_context, {
-          view: "toolbar_dropdown",
-        });
-      });
-      it("should dispatch a IMPRESSION with application_menu", async () => {
-        // means panel is triggered as a subview in the application menu
-        fakeElementById.hasAttribute.returns(false);
-        const messages = (await PanelTestProvider.getMessages()).filter(
-          m => m.template === "whatsnew_panel_message"
-        );
-        getMessagesStub.resolves(messages);
-        const spy = sandbox.spy(instance, "sendUserEventTelemetry");
-        const panelPingId = messages
-          .map(({ id }) => id)
-          .sort()
-          .join(",");
-
-        await instance.renderMessages(fakeWindow, fakeDocument, "container-id");
-
-        assert.calledOnce(spy);
-        assert.calledWithExactly(
-          spy,
-          fakeWindow,
-          "IMPRESSION",
-          {
-            id: panelPingId,
-          },
-          {
-            value: {
-              view: "application_menu",
-            },
-          }
-        );
-        assert.calledOnce(fakeSendTelemetry);
-        const {
-          args: [dispatchPayload],
-        } = fakeSendTelemetry.lastCall;
-        assert.propertyVal(dispatchPayload, "type", "TOOLBAR_PANEL_TELEMETRY");
-        assert.propertyVal(dispatchPayload.data, "message_id", panelPingId);
-        assert.deepEqual(dispatchPayload.data.event_context, {
-          view: "application_menu",
-        });
-      });
-    });
-    describe("#forceShowMessage", () => {
-      const panelSelector = "PanelUI-whatsNew-message-container";
-      let removeMessagesSpy;
-      let renderMessagesStub;
-      let addEventListenerStub;
-      let messages;
-      let browser;
-      beforeEach(async () => {
-        messages = (await PanelTestProvider.getMessages()).find(
-          m => m.id === "WHATS_NEW_70_1"
-        );
-        removeMessagesSpy = sandbox.spy(instance, "removeMessages");
-        renderMessagesStub = sandbox.spy(instance, "renderMessages");
-        addEventListenerStub = fakeElementById.addEventListener;
-        browser = { ownerGlobal: fakeWindow, ownerDocument: fakeDocument };
-        fakeElementById.querySelectorAll.returns([fakeElementById]);
-      });
-      it("should call removeMessages when forcing a message to show", () => {
-        instance.forceShowMessage(browser, messages);
-
-        assert.calledWithExactly(removeMessagesSpy, fakeWindow, panelSelector);
-      });
-      it("should call renderMessages when forcing a message to show", () => {
-        instance.forceShowMessage(browser, messages);
-
-        assert.calledOnce(renderMessagesStub);
-        assert.calledWithExactly(
-          renderMessagesStub,
-          fakeWindow,
-          fakeDocument,
-          panelSelector,
-          {
-            force: true,
-            messages: Array.isArray(messages) ? messages : [messages],
-          }
-        );
-      });
-      it("should cleanup after the panel is hidden when forcing a message to show", () => {
-        instance.forceShowMessage(browser, messages);
-
-        assert.calledOnce(addEventListenerStub);
-        assert.calledWithExactly(
-          addEventListenerStub,
-          "popuphidden",
-          sinon.match.func
-        );
-
-        const [, cb] = addEventListenerStub.firstCall.args;
-        // Reset the call count from the first `forceShowMessage` call
-        removeMessagesSpy.resetHistory();
-        cb({ target: { ownerGlobal: fakeWindow } });
-
-        assert.calledOnce(removeMessagesSpy);
-        assert.calledWithExactly(removeMessagesSpy, fakeWindow, panelSelector);
-      });
-      it("should exit gracefully if called before a browser exists", () => {
-        instance.forceShowMessage(null, messages);
-        assert.neverCalledWith(removeMessagesSpy, fakeWindow, panelSelector);
-      });
-    });
-  });
-});
diff --git a/browser/components/asrouter/tests/unit/content-src/components/ASRouterAdmin.test.jsx b/browser/components/asrouter/tests/unit/content-src/components/ASRouterAdmin.test.jsx
index 46d5704107..c5b0d09b39 100644
--- a/browser/components/asrouter/tests/unit/content-src/components/ASRouterAdmin.test.jsx
+++ b/browser/components/asrouter/tests/unit/content-src/components/ASRouterAdmin.test.jsx
@@ -1,4 +1,7 @@
-import { ASRouterAdminInner } from "content-src/components/ASRouterAdmin/ASRouterAdmin";
+import {
+  ASRouterAdminInner,
+  toBinary,
+} from "content-src/components/ASRouterAdmin/ASRouterAdmin";
 import { ASRouterUtils } from "content-src/asrouter-utils";
 import { GlobalOverrider } from "test/unit/utils";
 import React from "react";
@@ -259,4 +262,43 @@ describe("ASRouterAdmin", () => {
       });
     });
   });
+  describe("toBinary", () => {
+    // Bringing the 'fromBinary' function over from
+    // messagepreview to prove it works
+    function fromBinary(encoded) {
+      const binary = atob(decodeURIComponent(encoded));
+      const bytes = new Uint8Array(binary.length);
+      for (let i = 0; i < bytes.length; i++) {
+        bytes[i] = binary.charCodeAt(i);
+      }
+      return String.fromCharCode(...new Uint16Array(bytes.buffer));
+    }
+
+    it("correctly encodes a latin string", () => {
+      const testString = "Hi I am a test string";
+      const expectedResult =
+        "SABpACAASQAgAGEAbQAgAGEAIAB0AGUAcwB0ACAAcwB0AHIAaQBuAGcA";
+
+      const encodedResult = toBinary(testString);
+
+      assert.equal(encodedResult, expectedResult);
+
+      const decodedResult = fromBinary(encodedResult);
+
+      assert.equal(decodedResult, testString);
+    });
+
+    it("correctly encodes a non-latin string", () => {
+      const nonLatinString = "тестовое сообщение";
+      const expectedResult = "QgQ1BEEEQgQ+BDIEPgQ1BCAAQQQ+BD4EMQRJBDUEPQQ4BDUE";
+
+      const encodedResult = toBinary("тестовое сообщение");
+
+      assert.equal(encodedResult, expectedResult);
+
+      const decodedResult = fromBinary(encodedResult);
+
+      assert.equal(decodedResult, nonLatinString);
+    });
+  });
 });
diff --git a/browser/components/asrouter/tests/unit/unit-entry.js b/browser/components/asrouter/tests/unit/unit-entry.js
index f2046a81cb..2464b02c58 100644
--- a/browser/components/asrouter/tests/unit/unit-entry.js
+++ b/browser/components/asrouter/tests/unit/unit-entry.js
@@ -14,7 +14,7 @@ import FxMSCommonSchema from "../../content-src/schemas/FxMSCommon.schema.json";
 import {
   MESSAGE_TYPE_LIST,
   MESSAGE_TYPE_HASH,
-} from "modules/ActorConstants.sys.mjs";
+} from "modules/ActorConstants.mjs";
 
 enzyme.configure({ adapter: new Adapter() });
 
diff --git a/browser/components/asrouter/tests/xpcshell/head.js b/browser/components/asrouter/tests/xpcshell/head.js
index 0c6cec1ac8..fa361a00b9 100644
--- a/browser/components/asrouter/tests/xpcshell/head.js
+++ b/browser/components/asrouter/tests/xpcshell/head.js
@@ -81,10 +81,6 @@ async function makeValidators() {
       "resource://testing-common/UpdateAction.schema.json",
       { common: true }
     ),
-    whatsnew_panel_message: await schemaValidatorFor(
-      "resource://testing-common/WhatsNewMessage.schema.json",
-      { common: true }
-    ),
     feature_callout: await schemaValidatorFor(
       // For now, Feature Callout and Spotlight share a common schema
       "resource://testing-common/Spotlight.schema.json",
diff --git a/browser/components/asrouter/tests/xpcshell/test_PanelTestProvider.js b/browser/components/asrouter/tests/xpcshell/test_PanelTestProvider.js
index 3523355659..7e9892a595 100644
--- a/browser/components/asrouter/tests/xpcshell/test_PanelTestProvider.js
+++ b/browser/components/asrouter/tests/xpcshell/test_PanelTestProvider.js
@@ -22,7 +22,6 @@ add_task(async function test_PanelTestProvider() {
     cfr_doorhanger: 1,
     milestone_message: 0,
     update_action: 1,
-    whatsnew_panel_message: 7,
     spotlight: 3,
     feature_callout: 1,
     pb_newtab: 2,
diff --git a/browser/components/asrouter/yamscripts.yml b/browser/components/asrouter/yamscripts.yml
index de16c269a4..e52063c911 100644
--- a/browser/components/asrouter/yamscripts.yml
+++ b/browser/components/asrouter/yamscripts.yml
@@ -19,6 +19,7 @@ scripts:
     lint: =>lint
     build: =>bundle:admin
     unit: karma start karma.mc.config.js
+    import: =>import-rollouts
 
   tddmc: karma start karma.mc.config.js --tdd