Or you could've taken the 2 seconds to double check your info, the wiki page, or a previous time this item was asked about years back on this very subreddit.
Instead you chose to be a prude asswipe about it.
But if you had, you would have realized this item is, and has been, a bit of an enigma for a long while. The item itself is not from a mod. It is cut content from Nuka World. It's a legendary drop that does not spawn on legendary enemies. It's not in the loot tables/level lists, but Nuka World raiders have additional script that Commonwealth raiders do not, and part of that script is/was a miniscule chance of dropping this item.
So it's completely plausible the drop was not caused by a mod, or if it were, possibly a change to level lists or raider item pool, be it intentional, or if everything OP states is accurate, potentially small feature creep from undetermined mod.
But there are supposed cases of people on steam/reddit/etc having gotten it in unmodded or console over 5 years ago, and while it's mostly conjecture and hearsay, still an interesting item, that again, is still at the very least in the games code. So "didn't even know this was a thing" is a perfectly valid statement.
Rant over, but lord how annoying it is to see someone shitting on someone else for no fucking reason, for something they didn't know about, without even contributing any information to the discussion whatsoever. You could've done a number of constructive things, but instead chose to be belittling, ontop of being ill informed.