tl;dr In a recent thread on Mastodon, it was revealed that Ubuntu 23.04 users can’t install the Steam deb package from the Ubuntu archive without jumping through some technical hoops. It turns out this was a mistake, a bug was filed, and future builds shouldn’t have this problem.

Steam - the game store/launcher from Valve requires a bunch of 32-bit libraries to function. Many of the games that Steam installs also require many of these various libraries. These older games are likely never going to get updated to have 64-bit clean builds.

The thread on Mastodon brought up an expected thought process, though. The conspiracy theory-minded might (reasonably) think “This is Canonical breaking the deb, so you’re forced to use the snap”. But that doesn’t appear to be the case.

It’s just a simple mistake that is fixed, and now (a selected set of) i386 packages will be easily accessible again.