Ardupilot with downstream FBL controller for traditional heli

Greetings!

I just stumbled upon this article on DIYDRONES about an RC pass through to allow use of a traditional FBL controller

@tridge Where can I find more info about this firmware?

When in a nav mode does the Pixhawk still pass RC signals to the FBL controller in the same manner as a rx would?

I have long been interested in using a Pixhawk or the like as a
companion nav computer for use with a standard FBL controller. This
will definitely help get some influential users off the fence and return
to using single rotors vs ridiculous heavy lift multis. I personally
have a new build coming off the table soon and with what I have invested
in time and manufacturing cost I’m not comfortable jumping straight to a
pixhawk for the initial flight testing. Plus my pixhawk tuning skills
are not nearly up to par when it comes to helis. I am much more
comfortable with the flight behavior of a vbar or sk720 anyways.

Thanks
Eric