confusing 9020 form factor USFF and MFF (micro)

USFF uses internal psu

USFF mobo uses desktop ddr3 and has miniPCIe slot for wifi

9020 Micro uses AC adapter

9020 MFF mobo uses sodimm ddr3 and has slot 1 M.2 slot for wifi and slot 2 M.2 slot for ssd.  
(3020 MFF does not have slot 2 M.2)