Uhh...yeah. I'm probably going to wait a bit before telling people to pull and use that firmware. The comments at the end of the issue thread are not super encouraging:
I'll probably keep my own fork active for the time being. I get a lot of questions about ABL and double extruder setup and most of the folks I help aren't ready to jump into the tip-of-master fray on an active development project. Once things settle down, I may rebase onto the active Marlin tree.
I wrote up some instructions to try to address the repeated questions about firmware setup:
Comments are always appreciated.