C-String Naming In Handmade Hero

Why does Casey name c-strings and functions that deal with c-strings using 'Z' (for example: "S32FromZ", "WrapZ")?

Edited by Yuval Dolev on Reason: Initial post
You should ask him on the stream, but I suppose it's because they are Zero terminated (there is a byte with value zero at the end of the string).
Yeah, that makes sense. Thanks!