Examine source code of GitHub Trick or Treat

{
  "manifest_version": 2,
  "name": "GitHub Trick or Treat",
  "version": "1.2resigned1",
  "author": "Peter Bengtsson",
  "description": "Adds some nice tricks and treats to GitHub",
  "homepage_url": "https://github.com/peterbe/github-tricks-and-treats",
  "icons": {
    "48": "icons/trick-48.png",
    "256": "icons/trick-256.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://github.com/*/*/pull/*"
      ],
      "js": [
        "tricks.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{40d315db-2af6-4cfc-aa4f-f20916951eeb}"
    }
  }
}