SRE has a lot of different meanings, even in the science & technology world [1]. (I'll refrain from claiming that such is "common knowledge".)

[1] https://en.wikipedia.org/wiki/SRE

Most companies don't have them at all. Not by that name or anything like it, and if they have anyone kinda doing a similar-ish job you'd probably find their role and practices dissimilar enough that you'd not call them that, either.

Never heard of it before.

It's not.