text: An option :
  https://wiki.openstreetmap.org/wiki/Tag%3Ashop%3Dstreet_vendor
  
  Example to tag the times it's there :
  https://projets.pavie.info/yohours/?oh=May-Sep%2008:00-22:00
  
  https://wiki.openstreetmap.org/wiki/Tag:amenity%3Dtoilets