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 are now currently available on keyclack.com

Make example native QMK version (after setting up your build environment):

make jc65/v32u4:default

Make example ps2avrGB version (after setting up your build environment):

make jc65/v32a:default