I don’t know for sure, but since the feature was specifically added for Facebook sign-in compliance, my guess would be they designated the naming structure for the deleted accounts can’t think of any other reason anoek would choose such a long UID
But isn’t it comforting to know that the system would adequately handle if every human being on Earth created and deleted 2^95 accounts?
yes, yes, there are other practical limits that would be reached first before running out of unique names, like having enough memory to actually store all of those entries in a database, or the eventual heat death of the universe.