Examine source code of QRCodify

{
  "manifest_version": 2,
  "name": "QRCodify",
  "version": "1.2",
  "description": "Generate a QR Code of current page address.",
  "icons": {
    "48": "icons/icon.svg"
  },
  "page_action": {
    "default_icon": {
      "48": "icons/icon.svg"
    },
    "default_title": "QRCodify",
    "default_popup": "popup/popup.html",
    "show_matches": [
      "*://*/*"
    ]
  },
  "permissions": [
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{f7ecf372-06a6-472b-be88-d8000d998658}"
    }
  }
}