Examine source code of YT Smart Subs

{
  "manifest_version": 2,
  "name": "YT Smart Subs",
  "version": "1.33.92",
  "description": "Smart YouTube (together with Odysee and potentially any website) subscriptions feed without any need to log in.",
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png"
  },
  "browser_action": {
    "default_icon": "icons/icon-48.png",
    "default_popup": "popup.html"
  },
  "options_ui": {
    "page": "options.html",
    "browser_style": false,
    "open_in_tab": true
  },
  "permissions": [
    "storage",
    "tabs",
    "bookmarks",
    "downloads",
    "*://www.youtube.com/*",
    "*://youtube.com/*",
    "*://i.ytimg.com/*",
    "*://odysee.com/*",
    "*://*.odysee.com/*",
    "*://thumbnails.lbry.com/*",
    "*://kick.com/*",
    "*://*.kick.com/*"
  ],
  "optional_permissions": [
    "*://*/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      },
      "id": "{8c739e61-4665-4b27-892a-383aea9c7c77}"
    }
  }
}