remove-jewtube-tracker.user.js

// ==UserScript==
// @name        *chan Remove JewTube Tracker
// @namespace   Violentmonkey Scripts
// @match       https://boards.4chan.org/*/thread/*
// @icon        https://s.4cdn.org/image/favicon.ico
// @grant       none
// @version     1.0
// @author      -
// @description Remove the `si` parameter from JewTube links
// ==/UserScript==

function removeTrackingParameter() {
  const links = document.querySelectorAll("a.linkify.youtube")
  links.forEach((a) => {
    console.log("aa: " + a);
    const url = new URL(a.href)
    url.searchParams.delete('si')
    a.href = url.toString()
  })
}

setTimeout(removeTrackingParameter, 500)