Examine source code of Auto mute

{
  "applications": {
    "gecko": {
      "id": "autoMute@waldemar.b",
      "strict_min_version": "45.0a1"
    }
  },
  "permissions": [
    "tabs",
    "storage"
  ],
  "background": {
    "scripts": [
      "bg.js"
    ]
  },
  "options_ui": {
    "page": "options.html"
  },
  "description": "__MSG_extensionDescription__",
  "manifest_version": 2,
  "name": "__MSG_extensionName__",
  "default_locale": "en",
  "version": "1.2resigned1",
  "icons": {
    "48": "icons/icon.svg"
  }
}