Examine source code of Ideal Size

{
  "manifest_version": 2,
  "name": "__MSG_extensionName__",
  "description": "__MSG_extensionDescription__",
  "default_locale": "en",
  "version": "1.4.0",
  "applications": {
    "gecko": {
      "id": "idealsize@mozilla.kewis.ch"
    }
  },
  "icons": {
    "32": "images/addon.svg"
  },
  "permissions": [
    "storage",
    "activeTab"
  ],
  "optional_permissions": [
    "tabs",
    "https://docs.google.com/document*",
    "https://developer.mozilla.org/*",
    "https://bugzilla.mozilla.org/*",
    "https://github.com/*",
    "https://www.di.fm/*"
  ],
  "page_action": {
    "default_icon": "images/addon.svg",
    "default_title": "Ideal Size",
    "browser_style": false,
    "show_matches": [
      "https://docs.google.com/document*",
      "https://developer.mozilla.org/*",
      "https://bugzilla.mozilla.org/*",
      "https://github.com/*",
      "https://www.di.fm/*",
      "https://*.greenhouse.io/*"
    ]
  },
  "options_ui": {
    "page": "options/options.html",
    "browser_style": true
  },
  "background": {
    "scripts": [
      "background/background.js"
    ]
  }
}