Examine source code of Search For Domain

{
  "manifest_version": 2,
  "name": "Search For Domain ",
  "description": "Adds a context menu item that Searches For Domain",
  "version": "1.0",
  "applications": {
    "gecko": {
      "strict_min_version": "60.0a1"
    }
  },
  "icons": {
    "16": "icon/label.svg",
    "32": "icon/label.svg",
    "48": "icon/label.svg"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "menus",
    "clipboardRead",
    "clipboardWrite",
    "<all_urls>"
  ]
}