Examine source code of KeepSync

{
  "manifest_version": 3,
  "name": "KeepSync",
  "version": "1.0.0",
  "description": "Sync tabs across Chrome and Firefox browsers with self-hosted server",
  "permissions": [
    "tabs",
    "storage",
    "alarms",
    "downloads",
    "bookmarks",
    "history"
  ],
  "host_permissions": [
    "http://localhost/*",
    "https://*/*",
    "http://*/*"
  ],
  "background": {
    "scripts": [
      "src/background/background.js"
    ]
  },
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "action": {
    "default_popup": "src/popup/popup.html",
    "default_title": "Tab Sync",
    "default_icon": "icons/icon.svg"
  },
  "options_ui": {
    "page": "src/options/options.html",
    "open_in_tab": true
  },
  "content_security_policy": {
    "extension_pages": "script-src 'self'; object-src 'self'"
  },
  "author": "KeepSync",
  "homepage_url": "https://github.com/keepsync/extension",
  "browser_specific_settings": {
    "gecko": {
      "id": "tabsync@keepsync.com",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "bookmarksInfo",
          "browsingActivity"
        ]
      }
    },
    "gecko_android": {
      "strict_min_version": "142.0"
    }
  }
}