Working on charging stations I realized that OSM has a gap in the tagging when it comes to stations that have a cable and plug and ones that have only a socket and you need to bring you own cable.
There already had been a short discussion on the wiki page but it never yielded any results.
https://wiki.openstreetmap.org/wiki/Talk:Tag:amenity%3Dcharging_station#charging_cable_availability
Right now the only thing used in this direction is the plug: key but with very few examples
https://taginfo.openstreetmap.org/search?q=plug