Examine source code of nocontextmenu

{
  "manifest_version": 2,
  "name": "nocontextmenu",
  "version": "1.1resigned1",
  "description": "Disables context menu everywhere",
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "nocontextmenu.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{99b7c416-82dc-4f9f-9909-ebc038fddefc}"
    }
  }
}