Examine source code of QR Code Util

{
  "description": "A Firefox add-on that transforms between text and QR Code totally offline using the WebExtensions API.",
  "manifest_version": 2,
  "name": "QR Code Util",
  "version": "0.2.1resigned1",
  "default_locale": "zh",
  "homepage_url": "https://oceanapart.github.io/QR-Code-Util-Web-Extension/",
  "icons": {
    "32": "icons/QR-32.png",
    "48": "icons/QR-48.png"
  },
  "permissions": [
    "activeTab",
    "contextMenus"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": "icons/QR-32.png",
    "default_title": "QR Code Util",
    "default_popup": "popup/show_qrcode.html"
  },
  "commands": {
    "_execute_browser_action": {
      "suggested_key": {
        "default": "Ctrl+Q"
      }
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{98646173-7966-4aea-b2ca-4a7e75ff7682}"
    }
  }
}