SlackBuildsOrg/system/p7zip
..
doinst.sh
p7zip.info
p7zip.SlackBuild
README
slack-desc

7-Zip is a well-known file compression utility for windows.
p7zip is a ported version for linux with nearly the same capabilities.

If you want to build the new GUI, you have to pass GUI=yes to the script:
this requires an optional dependency, wxPython.