Examine source code of importICS

{
  "manifest_version": 2,
  "name": "importICS",
  "version": "0.5",
  "description": "Eases the import of ics files in google calendar. Still in developoment",
  "applications": {
    "gecko": {
      "strict_min_version": "50.0"
    }
  },
  "permissions": [
    "activeTab",
    "tabs",
    "storage",
    "downloads"
  ],
  "options_ui": {
    "page": "options.html",
    "browser_style": true
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  }
}