Teester
commented
6 years ago The wiki agrees with this.
According to https://wiki.openstreetmap.org/wiki/Tag:amenity=restaurant, diet:vegetarian and diet:vegan should indeed be used.
According to https://wiki.openstreetmap.org/wiki/Tag:shop%3Dbutcher, for Halal and Kosher butchers, butcher=halal and butcher=kosher should be used.
I'm not an expert in this area, but I think the tags diet:vegetarian/diet:vegan should be used instead of vegetarian/vegan. The latter only have minor usage in the OSM DB right now (see https://taginfo.openstreetmap.org/keys/vegetarian#overview and https://taginfo.openstreetmap.org/keys/vegan) Maybe this is also true for halal and kosher.