Now, the base rules are composed from microfiles *.part. I see no other way to handle...

[xorg/xkeyboard-config] / rules / base.ml1_s.part

! model     layout[1]   =       symbols
 $pcmodels      *       =       pc(%m)+%l[1]%(v[1])
  *             *       =       pc(pc105)+%l[1]%(v[1])