Examine source code of Toggle Fonts

{
  "manifest_version": 2,
  "name": "Toggle Fonts",
  "version": "2.2.0",
  "description": "__MSG_extensionDescription__",
  "browser_specific_settings": {
    "gecko": {
      "id": "{e7625f06-e252-479d-ac7a-db68aeaff2cb}",
      "strict_min_version": "61.0"
    }
  },
  "icons": {
    "24": "icons/togglefonts.svg",
    "32": "icons/togglefonts.svg",
    "50": "icons/togglefonts.svg"
  },
  "background": {
    "scripts": [
      "iconupdater.js",
      "background.js"
    ]
  },
  "browser_action": {
    "browser_style": true,
    "default_icon": "icons/togglefonts.svg",
    "default_title": "__MSG_button_title__",
    "theme_icons": [
      {
        "dark": "icons/togglefonts.svg",
        "light": "icons/togglefonts-light.svg",
        "size": 19
      }
    ]
  },
  "commands": {
    "_execute_browser_action": {}
  },
  "permissions": [
    "browserSettings"
  ],
  "default_locale": "en"
}