Собсно вот:
osm_user_name()
returns the OSM user name who last touched the current object [since r15246]
osm_user_id()
returns the OSM user id who last touched the current object [since r15246]
osm_version()
returns the OSM version number of the current object [since r15246]
osm_changeset_id()
returns the id of the changeset the current object was last uploaded to [since r15246]
osm_timestamp()
returns the time of last modification to the current object, as timestamp [since r15246]
https://josm.openstreetmap.de/wiki/Help/Styles/MapCSSImplementation#Evalexpressions