[ydant]

Since unp is a stock ticker, it's a little harder to find: https://github.com/mitsuhiko/unp

Looks like it might be in standard Ubuntu repositories:

https://manpages.ubuntu.com/manpages/xenial/man1/unp.1.html

[em-bee]

i use unar/lsar

https://theunarchiver.com/command-line https://github.com/MacPaw/XADMaster

in difference to unp and atool, unar does not depend on other tools to unpack the actual archive