Examine source code of Timer, Alarm & Stopwatch Pro

{
  "version": "0.1.6",
  "manifest_version": 2,
  "offline_enabled": true,
  "name": "Timer, Alarm & Stopwatch",
  "homepage_url": "https://mybrowseraddon.com/timer.html",
  "description": "An easy-to-use and lite timer, alarm, and stopwatch for your browser.",
  "commands": {
    "_execute_browser_action": {
      "suggested_key": {
        "default": "Ctrl+Shift+T",
        "mac": "Command+Shift+T"
      },
      "description": "Open Timer, Alarm & Stopwatch"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "alarms",
    "storage",
    "contextMenus"
  ],
  "browser_action": {
    "default_title": "Timer, Alarm & Stopwatch",
    "default_icon": {
      "16": "data/icons/16.png",
      "32": "data/icons/32.png",
      "48": "data/icons/48.png",
      "64": "data/icons/64.png"
    }
  },
  "icons": {
    "16": "data/icons/16.png",
    "32": "data/icons/32.png",
    "48": "data/icons/48.png",
    "64": "data/icons/64.png",
    "128": "data/icons/128.png"
  },
  "web_accessible_resources": [
    "data/icons/16.png",
    "data/icons/32.png",
    "data/icons/48.png",
    "data/icons/64.png",
    "data/icons/128.png"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{e13cdd68-e79e-4d01-962b-6046f2264ef1}"
    }
  }
}