To the best of my understanding, it wasn’t a “buyback” as the money came from the new investors and not from the company itself. The new owner of the options (or shares) that were previously mine is the new investor — and again, this is what I understand, it might or might not be the actual case. None of it is my business or of any interest to me, though.

Technical term is “tender offer”, not necessarily buyback - other investors can participate too