What I was going to ask as well, seems that people are getting dumber by the day.

At least in English, this appears to be slang that only recently leaked out of its original context. I've never heard the term before and whatever they used to look it up probably had no results.

The usual English term is "mid-level".

No, they weren't. They told me an awkward neologism for someone who isn't senior and isn't junior, and that means that neither they nor the original message tell me mid-level what.

So, no, they were not, or I would not have asked.