Examine source code of Toggl Stop

{
  "manifest_version": 2,
  "name": "Toggl Stop",
  "author": "Nicholas Rishel",
  "version": "1.2resigned1",
  "description": "Asks if you want to close the tab or window if a Toggl timer is running in a tab.",
  "icons": {
    "48": "tsicon48.png",
    "96": "tsicon96.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://www.toggl.com/app/timer",
        "https://toggl.com/app/timer"
      ],
      "js": [
        "toggl-stop.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{77ddf2d8-7b5f-49fd-88aa-032d6bd531db}"
    }
  }
}