The ability to see a list of web maps that a feature layer is included in would be helpful in several ways. One case would be when cleaning up / deleting data. For example, if you wanted to delete a feature layer it would be helpful to know if it was currently being used in a web map. Otherwise, it would get deleted and you may not realize that your public facing web map now has a missing data source for a layer.
This information could be in the overview or in the usage tab. I imagine that there is a way to get a list using the REST API, and there is definitely a way in python. But I think this would be helpful often enough to justify having a quicker/more user-friendly way to get the list.
