Hi!

Just a note that you should not change any objects solely to render on the default map. OSM is used by many maps and data consumers and what is rendered or parsed is different. For example, tagging this as a separate building means that the data now contains a separate building here (even if it looks like one on the default map).

https://wiki.openstreetmap.org/wiki/Tagging_for_the_renderer

I adjusted here to how building "air corridors" like this are usually tagged. Depending on which building it is part of - that building would include this shape and then the part itself duplicating the contour can specify how it's different.

Notably for levels/floors OSM maps this a little confusingly, but this is a 2 level building that starts at the second level - `building:levels=2` and
`building:min_level=1`.

https://wiki.openstreetmap.org/wiki/Key:building:min_level