No idea. This is just early beta code from Asus, it was provided so I could at least get started with merging it in (with only four models so far), and reunifying the mainline and AX models into one single code base. Asus will need to release non-beta code for all supported models first before I can get any idea of where I am going.
I used Adamm's amcfwm update to compile 386.1_a2 for the Rt-ac86u. Works pretty well. Router is running this firmware now.