Examine source code of Highlight Opened Tabs

{
  "manifest_version": 3,
  "name": "__MSG_extensionName__",
  "version": "1.2",
  "default_locale": "en",
  "description": "__MSG_extensionDescription__",
  "author": "Kustrica (Telegram: @kustric)",
  "homepage_url": "https://t.me/kustric",
  "action": {
    "default_title": "Highlight Opened Tabs",
    "default_icon": "icons/main-200.png"
  },
  "icons": {
    "200": "icons/main-200.png"
  },
  "permissions": [
    "tabs",
    "storage"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_start",
      "all_frames": true
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "highlightopenedtabs@kustrica.addon",
      "strict_min_version": "142.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}