ZIP is a popular archive file format, introduced in 1989 by Phil Katz and originally implemented in PKZIP utility by PKWARE.
Thanks to solid support of it in most desktop environments and operating systems, and algorithms / specs availability in public domain, it quickly became tool of choice for implementing file containers.
For example, Java .jar files, OpenDocument, Office Open XML, EPUB files are actually ZIP archives.
This page hosts a formal specification of ZIP archive file using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.