New signal at Groat Hill and Fenway has colors I've never seen before (Groat Hill)

They finally put a light at Groat and Fenway. Standard red/yellow/green on top, but there's two more I don't recognize. One's a deep amber. The other one I'd describe as "the color you see when you close your eyes too hard."

Sat through three full cycles. The amber seems to mean "proceed but with a sense of obligation." The other one, nobody moved. We all just sat there until it changed.

Anybody seen the municipal update on these? I don't want a ticket for guessing wrong.