[woodruffw]

I don’t think it’s this simple: you can still produce observable differentials with a single parser by using different options within that parser in different places. The ZIP format itself affords ample opportunities for that.

[hinkley]

The settings are at encode time. For two readers the results should be unambiguous.

[woodruffw]

There are plenty of decode-time knobs, even within a single ZIP parser. Here are just a few you could set while using libzip[1].

[1]: https://libzip.org/documentation/zip_open.html#DESCRIPTION

[hinkley]

That’s not a lot of settings, and that’s libzib, which is not zlib.

[woodruffw]

Differentials are oracular; you only need one bit. And I’m not claiming it’s in zlib, since zlib isn’t a ZIP library. TFA here is about ZIP differentials, not differentials in DEFLATE stream parsers.