After Python 3.15 got released with several of my fixes in Lib/wave.py I updated my 'newwave' package and put a new version out: https://codeberg.org/michielb/newwave/src/branch/main/CHANGES.md#0-32-0-2026-10-25
Use it for Python wave.py backports on older pythons, and also for new features that are not YET in python stdlib such as writing extended wave format and adding custom RIFF chunks, and metadata