Examine source code of WhoWorked

{
  "manifest_version": 2,
  "name": "WhoWorked",
  "description": "Track time directly from your browser with WhoWorked.",
  "version": "0.2.0",
  "short_name": "WhoWorked",
  "icons": {
    "16": "icon/16.png",
    "32": "icon/32.png",
    "48": "icon/48.png",
    "96": "icon/96.png",
    "128": "icon/128.png"
  },
  "permissions": [
    "storage",
    "notifications",
    "idle",
    "alarms",
    "contextMenus",
    "activeTab",
    "identity"
  ],
  "commands": {
    "toggle-timer": {
      "suggested_key": {
        "default": "Ctrl+Shift+U",
        "mac": "MacCtrl+Shift+U"
      },
      "description": "Start or stop the current timer"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "whoworked@whoworked.com",
      "strict_min_version": "142.0",
      "data_collection_permissions": {
        "required": [
          "personallyIdentifyingInfo"
        ]
      }
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "WhoWorked",
    "default_popup": "popup.html"
  },
  "options_ui": {
    "page": "options.html"
  }
}