In the 80ies many laboratory gear (like Tektronix and HP) used the Mostek MKB36000 masked ROMs.
The MOS2364 masked ROM was used by commodore.
These ROMs suffer from ROM rot and have a very unique pinout. The MCM68766 is a direct replacement EPROM for all these ROMs.
So supporting these EPROMs could help to repair these instruments without modifiying the original hardware
The MCM68364 and MCM68365 are nearly identical sister-models.