Examine source code of Normfall Manager

{
  "manifest_version": 2,
  "name": "Normfall Manager",
  "version": "8.20.3090.0",
  "description": "__MSG_extensionDescription__",
  "author": "Normfall GmbH",
  "browser_action": {
    "default_icon": {
      "20": "images/n_20x20.png",
      "40": "images/n_40x40.png"
    },
    "default_title": "__MSG_extensionDefaultTitle__",
    "default_popup": "popup/normfall_plugin.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "nfmanager@normfall.de"
    }
  },
  "default_locale": "de",
  "content_scripts": [
    {
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "js": [
        "content_scripts/plugin_content.js"
      ],
      "run_at": "document_end"
    }
  ],
  "permissions": [
    "<all_urls>",
    "nativeMessaging"
  ],
  "icons": {
    "16": "images/n_16x16.png",
    "20": "images/n_20x20.png",
    "32": "images/n_32x32.png",
    "40": "images/n_40x40.png",
    "44": "images/n_44x44.png",
    "48": "images/n_48x48.png",
    "50": "images/n_50x50.png",
    "128": "images/n_128x128.png",
    "150": "images/n_150x150.png"
  }
}