add a "depends" label for for containers submitted to FLIBS. This label would be populated with a human-readable description of the other containers (or host services) required to make this container work, e.g.

"depends" : "PostgreSQL or MySQL database"

this label would not be required if there are no dependencies. It would eventually be replaced by dependency labeling mandated by Fedora Modularity, once that team figures out dependency labeling. But for now, having human-readable dependencies listed is better than having nothing.