Examine source code of OMG! Ubuntu

{
  "name": "OMG! Ubuntu!",
  "version": "4.0.4",
  "manifest_version": 2,
  "description": "The official OMG! Ubuntu extension",
  "icons": {
    "19": "images/icon_active19.png",
    "48": "images/icon_logo48.png",
    "128": "images/icon_logo128.png"
  },
  "browser_action": {
    "default_icon": {
      "19": "images/icon_active19.png",
      "38": "images/icon_active38.png"
    },
    "default_title": "OMG! Ubuntu!",
    "default_popup": "popup.html"
  },
  "background": {
    "page": "background.html",
    "persistent": false
  },
  "permissions": [
    "notifications",
    "alarms",
    "storage",
    "https://*.omgubuntu.co.uk/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "omgubuntu@joeysneddon",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    },
    "gecko_android": {
      "strict_min_version": "142.0"
    }
  }
}