You mean the hardware license keys for the MPEG-2 decoder? That was very stupid, but I bet it was something the Raspberry Pi people had to do to make the board cheaper (probably through cheaper SoC). So rather than paying (fake numbers here) $5 per processor IC, they paid $3 with the decoder option available.
It sucked at the time, but thankfully the later Raspberry Pi 3B was powerful enough that that wasn’t needed anymore (it was still available on the 3B, but IDK about the 4B).
It sucked at the time, but thankfully the later Raspberry Pi 3B was powerful enough that that wasn’t needed anymore (it was still available on the 3B, but IDK about the 4B).