They also display when you add a schema to a map and choose a schema on a feature
Can you remove an in use schema from a map and does that break anything? (I don't think so)
On a schema, you can see which maps it's associated with and how many features use it (and this can link to the search screen to filter a map to a particular schema)
Needs some polish, I think.
I find myself wondering which schemas are used where.
There's a few ways we could solve, e.g. getting to schemas via MapsManager, showing which maps are used on a schema, et cetera.
Maybe also hero icons for them?
To ponder.