Hi,

ID got it wrong on crossings... crossing=* is to say what the type is, traffic_signal, uncontrolled, unmarked etc. Someone even inserted a line "crossing=marked (used by iD preset) - with crosswalk, with or without traffic lights", but that does not legitimize it... anyone can edit the wikis.
The crossing:marking is not =yes, it's meant to say e.g. zebra. It's like the many barrier=yes, which is meaningless.... barrier=gate/block/fence tells what they are. The root wiki actually says "crossing:markings=* - to tag the existence and style of pedestrian crossing markings"... zebra, rainbow, there's a whole bunch of esoteric styles, allowing to also add the colours of the markings.
In short now we have a bunch more BeeEs tagging combos from the ID automaton.... crossing=marked + crossing:markings=yes, doesn't look good, neither adding another version to the object history for nop.
One of the many reasons I very rarely use ID to include it's poor poor handling of relations in any form, but that's a debate of it's own and endless.

ciao ciao