What does this symbol mean?

[Madison]

Thanks, everyone.

A coworker that's more experienced working with architects told me it's a light source and the subscript represents the circuit it's on, but it's on a drawing that has no other light sources and it's a non-standard symbol, so I'm skeptical that's the case.

Also, several of them appear in the middle of structures that stretch from floor to ceiling, so it'd be peculiar to put in a light where nobody will see it.

The search continues...