The JC65 PCB actually has two revisions: A QMK native version, and a PS2AVRGB version. Jchan offered both PCBs as options during the M65-A Round 1 group buy, and were also available choices for the 65% acrylic case group buy. In the near future both PCB versions should be available from keyclack.com when the storefront part opens.
These docs are for the QMK version of the PCB. More info on qmk.fm
Make example for this keyboard (after setting up your build environment):
Or to make and flash: