BF256, Obsolete component. The BF256B is similar to the 2N5485. The NTE451 is a very close match.
I often wonder if there's a resource out there for finding the SMT part numbers for THT transistors - many have simply moved unchanged into different packages with different part numbers that often don't bear much relation to the original part number. Here the part numbers share the last 3 digits which confirms its the same part.