Gentoo / Pentoo Distributions Gentoo is the base which Pentoo is built from.
Gentoo is an operating system that was designed ages ago with the intentions of being a secure, extremely configurable operating system (for those willing to take the plunge).
Essentially it allows one to package their own repos to download for their OS (i.e., instead of just de facto using 'sudo apt install' / 'pacman -S ...', etc.).
For some this is an advantage - for others this could be a pain in the ass.
Pentoo Alt Distribution Person behind Pentoo (maintainer) is a cocky asshole because I offered to contribute some of the things that I had documented personally along the way as I was spinning up the operating system for potential use on one of my personal computers, but he refused the documentation assuming that everything had been covered (and it hadn't).
More Information 1.
Gentoo Documentation (there's a mountain of it) -
https://www.gentoo.org/support/documentation/ [some of it is also applicable to other operating system as well of course]
2.
Pentoo (download for the distro if you're curious) -
https://www.pentoo.ch/^^ Even though Pentoo is a 'live distribution', installing it on your computer for persistence is more than feasible if you're looking to do so.