It’s not a bug, at least by how we define bugs. Generally we consider bugs functionality that isn’t working as intended, and these were intentional changes. More of a UX issue in this case.
the information is available on topic lists, in a way that’s accessible and reached the same by everyone:
It is harder to find, and if there’s broad interest in making the descriptions more visible that’s a feature request we can consider.
We also provide the Tag Banners component, which puts descriptions into a banner on the tag topic lists.
Tooltips on tags aren’t really something we can implement well as an option, because they have a similar issue as the title attribute with data asymmetry… hover tooltips are fine on desktop, but don’t work on mobile, especially considering tags are usually links so a click activation is already spoken for.