Examine source code of TikTock

{
  "manifest_version": 2,
  "name": "TikTock",
  "version": "1.0.2",
  "description": "Create a simple pomodoro timer.",
  "icons": {
    "64": "icons/icons-64.png"
  },
  "permissions": [
    "activeTab",
    "storage"
  ],
  "browser_action": {
    "default_icon": "icons/icons-32.png",
    "default_popup": "popup/tiktock.html",
    "theme_icons": [
      {
        "light": "icons/icons-32-white.png",
        "dark": "icons/icons-32.png",
        "size": 32
      }
    ]
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{bf9691a0-d890-4a55-9bd0-888be1d736d7}"
    }
  }
}