Examine source code of UTM Remover

{
  "manifest_version": 2,
  "name": "UTM Remover",
  "version": "1.0.3resigned1",
  "description": "Remove `utm_*` params from the query string before the request.",
  "applications": {
    "gecko": {
      "id": "utm-remover@localhost.localdomain",
      "strict_min_version": "53.0"
    }
  },
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "*://*/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  }
}