Examine source code of Marko - Bookmark Manager

{
  "manifest_version": 3,
  "name": "__MSG_extensionName__",
  "version": "1.0.0",
  "default_locale": "en",
  "description": "__MSG_extensionDescription__",
  "browser_specific_settings": {
    "gecko": {
      "id": "marko@marko-bookmarks.app",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "authenticationInfo",
          "bookmarksInfo",
          "browsingActivity"
        ]
      }
    },
    "gecko_android": {
      "strict_min_version": "142.0"
    }
  },
  "permissions": [
    "activeTab",
    "tabs",
    "storage",
    "contextMenus",
    "bookmarks",
    "alarms"
  ],
  "host_permissions": [
    "https://*.firebaseapp.com/*",
    "https://*.googleapis.com/*",
    "https://*.cloudfunctions.net/*",
    "https://*.gstatic.com/*",
    "https://identitytoolkit.googleapis.com/*",
    "https://securetoken.googleapis.com/*",
    "https://marko-bookmarks.app/*"
  ],
  "action": {
    "default_popup": "popup-router.html",
    "default_title": "__MSG_extensionName__",
    "default_icon": {
      "16": "icons/icon16.png",
      "48": "icons/icon48.png",
      "128": "icons/icon128.png"
    }
  },
  "commands": {
    "open-marko": {
      "suggested_key": {
        "default": "Alt+Ctrl+M",
        "mac": "Alt+Command+M"
      },
      "description": "__MSG_openMarkoCommand__"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "https://marko-bookmarks.app/*"
      ],
      "js": [
        "contentScript.js"
      ],
      "run_at": "document_start"
    }
  ],
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "content_security_policy": {
    "extension_pages": "script-src 'self'; object-src 'self';"
  }
}