Examine source code of GitHub Board colorer

{
  "name": "GitHub Board colorer",
  "version": "1.0",
  "description": "Color your project board",
  "manifest_version": 2,
  "icons": {
    "16": "icon16.png",
    "32": "icon32.png",
    "64": "icon64.png",
    "128": "icon128.png"
  },
  "content_scripts": [
    {
      "js": [
        "index.js"
      ],
      "css": [
        "styles.css"
      ],
      "matches": [
        "https://github.com/*"
      ]
    }
  ]
}