Unable to answer "What can be left here for recycling?" – underground: Recycling Bin – https://osm.org/node/8737046124 via StreetComplete 56.1:

These are six containers for three different types of trash. The ones in the middle have no readable markings on them.

Attached photo(s):
https://westnordost.de/p/201130.jpg
https://westnordost.de/p/201131.jpg
https://westnordost.de/p/201132.jpg
https://westnordost.de/p/201133.jpg