Examine source code of UserSearch

{
  "manifest_version": 2,
  "name": "UserSearch",
  "description": "Contextual menu for quick search of NZB files according to the selected text.",
  "version": "3.2",
  "homepage_url": "https://developer.mozilla.org",
  "developer": {
    "name": "Usernet"
  },
  "icons": {
    "48": "icons/userico.png"
  },
  "background": {
    "scripts": [
      "userapi.js"
    ]
  },
  "permissions": [
    "menus",
    "activeTab",
    "contextMenus",
    "clipboardWrite"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{94612e11-8264-40d8-843a-b77649808faa}"
    }
  }
}