I wonder how it evolved into the modern British slang of “git”. To quote Wikipedia [0]

“modern British English slang, a git (/ɡɪt/) is a term of insult used to describe someone—usually a man—who is considered stupid, incompetent, annoying, unpleasant, or silly.“.

And “ Git is a popular open-source software for version control created by Linus Torvalds. Torvalds jokingly named it "git" after the slang term, later defining it as "the stupid content tracker".”

[0] https://en.wikipedia.org/wiki/Git_(slang)

"Listen baby, they're playing uncer song..."

"Git should get a room!"

n̥ is just the "not" prefix. The "ero" is the real root. The prefix applies to the root first, and then the other pieces have their meanings, usually. (Its a reconstructed language. There are both exceptions and things we don't know.)

"n̥-s-ero-" is sort of < "not" next-is-plural "mine" >.

So, plural-(invert mine). Or roughly close to "we".

"n̥-h-ero-" is sort of < "not" next-is-inclusive-plural "mine" >.

So, plural-(group (invert mine)). Or roughly close to "us".

But both are pretty close to the same meaning. High German maintained a lot of PIE, and is very close in a lot of ways. Though... Welsh is closer.