This isn't an oddity or issue with Python zip creation, it's expected behaviour as per ISO/IEC WD 21320-1[1]. > The compression method shall be either 0

This isn't an oddity or issue with Python zip creation, it's expected behaviour as per ISO/IEC WD 21320-1[1]. > The compression method shall be either 0 (“stored”) or 8(“deflated”). The format does not prescribe a compression algorithm (many could be available for use). It's merely a container. [1] ISO/IEC WD 21320-1, Document Container File - Part 1: Core - https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.397.7181&rep=rep1&type=pdf https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.39...