A DNF .repo file has baseurl and gpgkey lines full of $releasever, $arch, and $basearch. Since these aren't set anywhere in the file, how do they get real values, and what do they resolve to?

You want to write a single GUI installer that works on Fedora, Arch, and openSUSE without caring which package backend each uses. What library was meant to give you that, and why would relying on it today be a bad bet?

A developer needs PHP 8.1 available on one RHEL box while another team needs 8.2, both from the standard package sources. What Red Hat mechanism makes parallel versions of the same program possible, and what was it originally called?

The RPM database has drifted out of sync with reality after someone cleaned up disk space. What did they most likely do wrong, and where does that database actually live?

Reading the filename abc-2.0.7-1.x86_64.rpm, what do the 2.0.7, the 1, and the x86_64 each tell you — and how can a package's release number climb while its version stays fixed?

You spot an unfamiliar config file in /etc and want to know which package put it there, read that package's description, then see everything else it installed. Which three rpm queries do you run, in that order?

Your Python install is misbehaving and you suspect a file was tampered with since installation. Which rpm command checks whether the installed files still match the package, and what does an empty result mean?