Examine source code of github-icons

{
  "manifest_version": 2,
  "name": "plgn",
  "version": "1.1resigned1",
  "description": "Adds an icon based on file extension while browsing a repository.",
  "icons": {
    "48": "icons/logo.png",
    "64": "icons/logo.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.github.com/*"
      ],
      "js": [
        "github-icons.js"
      ]
    }
  ],
  "web_accessible_resources": [
    "icons/*.svg"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{591fc872-4df9-44a6-9060-f8e3cb109c15}"
    }
  }
}