Yamagi Patch. Works on GOG and Steam Versions. Easiest way to find it is on Steam. Windows 10 will block it. So, continue anyway after more info and install it into the appropriate folder. I will include the folder with thew Self extractor extension. Sorry, can't file is too big. File is 269 MB, LTT only allows 20MB. I did try.
Here is the link.
Hope this helps anyone with the quake 2 problem with fullscreen. This brings you to Steam page right before you leave to download the extension. after downloading, extract to the quake2 folder using the extension. You will need to know where Quake II folder is.
Patch works in Windows 10 on GOG and Steam installations. Also has music. Awesome patch.