Examine source code of Offline Tabs

{
  "author": "igorlogius",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "Toggle Tab Network State"
  },
  "commands": {
    "_execute_browser_action": {
      "suggested_key": {
        "default": "Ctrl+Alt+I"
      }
    }
  },
  "description": "Change the connectivity (aka. network state) for tabs",
  "icons": {
    "256": "icon.png"
  },
  "manifest_version": 2,
  "name": "Offline Tabs",
  "permissions": [
    "activeTab",
    "menus",
    "<all_urls>",
    "webRequest",
    "webRequestBlocking"
  ],
  "version": "1.0.2",
  "browser_specific_settings": {
    "gecko": {
      "id": "{19cd6c6c-3c65-4b20-a3e9-485f878a97ca}"
    }
  }
}