Thank you for this! I have seen this before but I forgot the name. Bookmarking it and I'll probably create a simple bookmarklet so that I can quickly open it up on the current tweet

edit: in case anyone is interested, here's the code for the bookmarklet to turn the current tweet into a threadapp thread. This is not very deeply tested but it worked with the current tweet above so YMMV:

  javascript:(function(){window.location.href = 'https://threadreaderapp.com/thread/' + window.location.pathname.split('/').pop(); })();