removeSponsoredPostsLive.js

const domInsertionObserver = new MutationObserver(function(mutationsList){
  const addedPosts = [...mutationsList]
    .filter(mutation => mutation.type === 'childList' && mutation.addedNodes.length)
    .flatMap(mutation => [...mutation.addedNodes])
    .filter(addedNode => typeof addedNode.id === 'string' && addedNode.id.startsWith('u_fetchstream'))
});
domInsertionObserver.observe(document.querySelector('div[id^=feed_stream]'), { childList: true, subtree: true });