Clear all cookies in a userscript?

How to clear all cookies or at least restart the browser in a tampermonkey/greasemonkey script?

Answer

To clear the cookies edit your Chrome shortcut (or write a shell script in Linux/MacOS) and add

 --remote-debugging-port=1234

(or use a random port number that’s not used by other processes) so you can send Network.clearBrowserCookies RDP command:

// ==UserScript==
// @name        Clear cookies
// @match       https://www.example.org/*
// @grant       GM_xmlhttpRequest
// @connect     localhost
// ==/UserScript==

GM_xmlhttpRequest({
  url: 'http://localhost:1234/json',
  responseType: 'json',
  method: 'GET',
  onload(e) {
    const ws = new WebSocket(e.response[0].webSocketDebuggerUrl);
    ws.onopen = () => {
      ws.send(JSON.stringify({id: 1, method: 'Network.clearBrowserCookies'}));
    };
    ws.onerror = console.warn;
  },
});