[idoubtit]

What is the open standard?

As far as I know, the ISO standard for zip only specifies two compression methods: "store" (no compression) and "deflate". If I follow that, when I create a zip file, I know it's not performant, but at least it's almost universal (except for file ownership, permissions, character encoding and anything modern).

The corporate PKWARE has added other compressions to their original zip software, but those are not in the standard. They will not work for an EPUB, a LibreOffice file, etc. If I want a good compression, I reach for zstd (often through `tar`) or 7z if I want more portability.