Examine source code of Yin-Yang

{
  "manifest_version": 2,
  "name": "Yin-Yang",
  "version": "1.3.1",
  "description": "Changes automatically to a theme as set in the application Yin Yang",
  "icons": {
    "48": "assets/logo.svg",
    "96": "assets/logo.svg"
  },
  "applications": {
    "gecko": {
      "id": "firefox-extension@yin-yang.org"
    }
  },
  "background": {
    "scripts": [
      "theme_select.js"
    ]
  },
  "permissions": [
    "management",
    "browserSettings",
    "nativeMessaging",
    "alarms"
  ]
}