The tags details can be found in the tagging section of the linked page but they are:
sensory_friendly=*
sensory_friendly:accommodation=*
sensory_friendly:conditional=*
source:sensory_friendly=*
amenity=quiet_room
I was inspired by Walmart stores prominently displaying “sensory-friendly” hours. One of the people on that Walmart initiative team is the one who helped write version 2 of the proposal, @PCarew_EG (Phil). The proposal strongly recalls the widely established wheelchair=* tag, which should help in understanding and adoption. I will be at SotM so we can chat there if you like. I’ve messaged you on the conference app and emailed you directly.
As far as next steps, it’s still a new tag, adoption is the next step and talks like yours can help let people know about this type of accessibility tagging.