This JOSM style displays useful information to help indoor map edition. It highlights rooms, corridors, stairs and elevators. In addition, some kind of nodes which are important inside a building will be represented also:
- Indoor beacons such as NFC, QRs and iBeacons
- Objects related to emergency situations: fire extinguishers, assembly points...
Download the zip and extract its content. Follow the instructions here http://josm.openstreetmap.de/wiki/Styles#Addingownstyles to add the style