MV3 webRequest demo. To view the console, you may need to manually open devtools for the service worker. On Chrome, visit chrome://serviceworker-internals and search for the service worker registered to `chrome-extension://<extension-id>/` where extension-id is the ID of your extension.

background.js

// Copyright 2020 Google LLC.
// SPDX-License-Identifier: Apache-2.0

chrome.webRequest.onBeforeRequest.addListener(
  (details) => {
    console.log('onBeforeRequest', details)
  },
  {urls: ["<all_urls>"]},
);

LICENSE

 Copyright 2020 Google LLC

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at

     https://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.

manifest.json

{
  "name": "MV3 WebRequest Demo",
  "version": "1.0",
  "manifest_version": 3,
  "permissions": [
    "webRequest"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "background": {
    "service_worker": "background.js"
  }
}

I was having a problem using this API, in the end, comparing my code to yours I found out that the problem has that I was defining the handler function after adding the listener.
I am still a little confused about when the order of the code matters in javascript, but from now on, I'll always add listeners at the end of the code hahaha
Thank you a lot, S2

Thanks man, This was really helpful.