This file originates from XDA, from a post written by user "GoodSoul". See: https://forum.xda-developers.com/showpost.php?p=79548858&postcount=6 Is he the author? Did he find a script and changed it? No idea.
However. The normal script dumps out all the files, resulting in a fully extracted .bin. But we don't need that. We need boot images. So I just changed a line to do that and also made an executable + GUI to extract boot images.
Have fun.
If you are the original author, let me know, I'll add your name, repo, everything here. I did try to search Github but could not find the source to fork it.