Examine source code of Rotating Color Theme

{
  "manifest_version": 2,
  "name": "Rotating Color Theme",
  "version": "1.0.2resigned1",
  "description": "Gives every window a different color",
  "applications": {
    "gecko": {
      "id": "randomcolortheme@weinshel.net",
      "strict_min_version": "58.0"
    }
  },
  "permissions": [
    "storage",
    "theme"
  ],
  "background": {
    "scripts": [
      "lib/browser-polyfill.min.js",
      "background/background.js"
    ]
  },
  "options_ui": {
    "page": "options/options.html",
    "browser_style": true,
    "chrome_style": true
  }
}