Examine source code of Color Tabs

{
  "manifest_version": 2,
  "name": "Color Tabs",
  "version": "1.1.0",
  "description": "Firefox tabs custom color based on URL",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "theme",
    "tabs",
    "storage"
  ],
  "options_ui": {
    "page": "options/options.html",
    "browser_style": true
  },
  "icons": {
    "48": "icons/icon-48.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{6300631d-7247-4250-8723-4407089c8578}"
    }
  }
}