Examine source code of Force Google UDM=14

{
  "manifest_version": 2,
  "name": "Force Google UDM=14",
  "version": "1.1",
  "description": "Forces Google to use udm=14 in search queries.",
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "*://www.google.com/search*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{403483ce-b8c1-4902-a97f-79bc1cf68e4c}",
      "strict_min_version": "102.0"
    }
  }
}