Examine source code of QR Print

{
  "name": "QR Print",
  "version": "0.82resigned1",
  "description": "Backlinks for your printouts",
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "js/qrcode.min.js",
        "js/inject.js"
      ],
      "css": [
        "css/inject.css"
      ]
    }
  ],
  "background": {
    "persistent": false,
    "scripts": [
      "js/background.js"
    ]
  },
  "browser_action": {
    "default_icon": "img/app-icon-128.png",
    "default_title": "Print this page with QR links"
  },
  "permissions": [
    "activeTab",
    "*://*/*",
    "contextMenus"
  ],
  "icons": {
    "16": "img/app-icon-128.png",
    "48": "img/app-icon-128.png",
    "128": "img/app-icon-256.png",
    "256": "img/app-icon-256.png"
  },
  "manifest_version": 2,
  "content_security_policy": "script-src 'self'; object-src 'self'",
  "browser_specific_settings": {
    "gecko": {
      "id": "{d8bee17e-d592-41f0-b30c-b2d7b6b47eb1}"
    }
  }
}