* Will be utilized in the X16
Alongside VERA, the YM2151 will be used in Commander X16.
Source:
https://www.commanderx16.com/faq.html
* Boards already shipped.
Since the 8-Bit Guy already ships X16 boards to the customers, I guess the YM2151 should be considered as an official part of the X16 sound system (albeit in the FPGA).