@ikreymer's testcase for https://github.com/electron/electron/issues/27768

main.js

const {app, BrowserWindow} = require('electron');
const path = require('path');

var mainWindow;

async function init(url) {
   // load about:blank first, just in case, before attaching debugger
   // (doesn't seem to make a difference)
  await mainWindow.loadURL("about:blank");
  
  mainWindow.webContents.debugger.attach("1.3");

  await initTarget();

  mainWindow.webContents.debugger.on('message', async (event, method, params, sessionId) => {
    if (method === 'Fetch.requestPaused') {
      console.log("url", params.request.url);
      await send("Fetch.continueRequest", {requestId: params.requestId }, sessionId);
    }
    if (method === "Target.attachedToTarget") {
      await initTarget(params.sessionId);

      if (params.waitingForDebugger) {
        await send('Runtime.runIfWaitingForDebugger', null, params.sessionId);
      }
    }
  });

  await mainWindow.loadURL(url);
}

async function initTarget(sessionId) {
  await send("Fetch.enable", {patterns: [{urlPattern: "*", requestStage: "Response"}]}, sessionId);

  await send("Target.setAutoAttach", {autoAttach: true, waitForDebuggerOnStart: true, flatten: true }, sessionId);
}

async function send(method, params, sessionId) {
  if (sessionId) {
    await mainWindow.webContents.debugger.sendCommand(method, params, sessionId);
  } else {
    await mainWindow.webContents.debugger.sendCommand(method, params);
  }
}

app.whenReady().then(() => {
  mainWindow = new BrowserWindow({
    width: 1024,
    height: 768,
    webPreferences: {
      contextIsolation: true,
    }
  });

  init("https://oembed.link/https://www.youtube.com/watch?v=M7lc1UVf-VE");
});