[alecmg]

Last I was dealing with zip files in Python 3 years ago, I was unpleasantly surprised that there is no way to open Zip64 archives.

It is a semi-proprietary format not supported by zlib. Some tools, most notably Windows will sometimes use it to create large zip archives that go beyond limits of original zlib. An unsuspecting user would compress some files and there is no warning which format has been used.

[michalc]

To check, do you mean Deflate64?

I think Zip64 _is_ supported by Python, and doesn't really involve anything at the zlib level(?)

(The reason I'm asking: a recent answer at https://stackoverflow.com/a/67579486/1319998 mentions Deflate64 and Windows)