Of course a simple hex editor or even xxd will easily show you a hex/ascii representation of a binary file. But is there any good software that understands many binary formats and can for example show me what header values a gzip file contains?
I think a terminal application that understands this for many different formats and easily allows you to add more formats would be very helpful
$ xxd /bin/ls | vi - /to open file : xxd -r /to save files
for gzip files, extract those, that is the best representation of what’s inside IMO, then look at those binary individually. Good luck!