Two things:

First, don't assume that just because you've never heard a word, that means no one has heard of it. There are quite a lot of us who know what the fediverse is.

Second, and this is a little pedantic, fediverse is a portmanteau, not an acronym.

Well, I've been here for over 3 years and never even seen fidiverse once in the news feed. Nor did use or needed.

And that's totally fine and a legitimate experience. Just be open to the idea that that is your experience, and not also the world's.

Fediverse isn't an acronym, nor is it a term "no one's heard of". You haven't heard it before, and it's great to explain it, but don't project that either.

IMO It would be worse to editorialise the submission title

I've seen fediverse numerous times on HN