toilets:private_stalls= : Let’s use specific measurements eg toilets:stalls:enclosed= directly, not vague judgements as a “private” feeling
=partially : I don’t get your definition. It looks to be whether the stalls are partially enclosed to me.
=yes : As you used =partially , I would think this is an unspecific positive more, ie “some” vs all stalls
Full-height enclosure isn’t the sole possibility. Stalls can have a short “slot” for liquids (and air?) only, only revealing shoe bottoms very close. They can be gapped, or enclosed, at the top or bottom only.
The format does get complicated if you need to consider the number of stalls with this extent of enclosure. Hopefully there isn’t a mix of them?
I mentioned toilets:stalls:*= , as it could be eg toilets:stalls:count= for the number of all of them. toilets:num_chamber= is imported, and awkwardly named. There may be unenclosed WC. Urinals aren’t “chamber”. Recently I remembered there are family stalls with 2 WC inside, one of them child-sized. How to combine prefixes and suffixes to describe the size of a toilet