I’ve been creating a draft to deprecate because I consider busway=* (for bus lanes, at least, still can be used in combination with highway=busway) to be unnecessary with bus:lanes (in fact, I’ve removed them from existing highways in my regions already) and also documenting busway=opposite for completion since busway=opposite_lane will also get deprecated.
This got now finished so I’m also asking someone to cross post this announcement on the tagging mailing list on my behalf by sending an email to: tagging@openstreetmap.org
I’ve decided to send the RFC by myself.