...://github.com/BENICHN/VGMGUI/releases
To convert WAV or MP3 files back into WEM files, you'll need Sound Editor 2018 https://smacktalks.org/forums/topic/68040-sound-editor-2018-released-version-141/ (scroll down to "Download (installer)" and "Reveal hidden contents")
Tutorial here: https://youtu.be/9km8OEjIamo
NOTE: v1.0 still has a known bug where it randomly crashes when you click something. This will be fixed soon.