How to extract data from archive with signature 789C?

Question

Google say what is this zip archive, but I cannot its extract by ICSharpCode.SharpZipLib and Zlib.net libraries.

Answer 1

That is a zlib (RFC 1950) header. You can use the zlib library to decompress it.

Answer 2

I found offzip.exe at http://aluigi.altervista.org/mytoolz.htm to be super helpful to expand RFC 1950s.