Examine source code of Pull The Lever! Tab Saver

{
  "manifest_version": 2,
  "name": "__MSG_title__ __MSG_subtitle__",
  "description": "__MSG_desc__",
  "version": "1.1",
  "background": {
    "scripts": [
      "node_modules/webextension-polyfill/dist/browser-polyfill.min.js",
      "out/background.js"
    ]
  },
  "browser_action": {
    "default_title": "__MSG_title__",
    "default_icon": {
      "48": "img/button_save_48.png",
      "96": "img/button_save_96.png",
      "128": "img/button_save_128.png"
    }
  },
  "permissions": [
    "tabs",
    "storage"
  ],
  "applications": {
    "gecko": {
      "id": "pull-the-lever@thedaviddelta.com"
    }
  },
  "icons": {
    "48": "img/button_save_48.png",
    "96": "img/button_save_96.png",
    "128": "img/button_save_128.png"
  },
  "default_locale": "en"
}