(off topic)

> If nothing happens, I also would like to write a zstd module for stdlib before the end of the year, but I dare not promise this.

I suggest you to publish it on PyPI. Once it will be mature, you can propose it on python-ideas. Last time someone proposed a new compression algorithm to the stdlib, it was rejected if I recall correctly. I forgot which one was proposed. Maybe search for "compresslib" on python-ideas.