yes but in this cases it is not foot:backward=yes - there it is foot:backward=no!
So the statement that oneway=yes inplies foot:backward=yes ist totally wrong!

oneway never adds a “access=” yes. it only sets one direction “access” to no in the one or the other direction.

On roads:
oneway=yes overwrites all types of “vehicle”:backward with no
oneway=-1 overwrites all types of “vehicle”:forward with no
oneway=no does nothing.

2 Likes