Well I'm here and I will give you my absolutely best and most professional assessment. I have no idea. The holes are not like any shavette blade I've run into, which are usually notches. Just based on that alone I would guess that it's proprietary for a particular razor. I'll run some image searches and matches to see if anything shows up. Quite puzzling.
If I had to guess, I would say that it is made from the same strip of metal that DE blades are made from. I would also say that my best guess is that the blade is for a medical/surgical single use disposable razor, similar to this one.
It came out of a bulk pack of pre split DE blades and there were more like it. It was wrapped just like a pre-split DE blade. Just no name on the wrappers, or blade. ?. It is a great blade but the only guidance I have is what I have purchased, Derbys, Sharks, and Royal Reds, but resembles none.