Juste one dummy question
To what correspond the wmaster0 interface ?
It seems to be created by the mac80211 stack, I presume it come from the master mode code part of mac80211 that has been partly removed.
It is related to the mac80211 stack. It was useful in the early days of mac80211 but the developers are trying to move away from needing it now due in part to the confusion it causes.