I know this completely doesn’t apply to the US, but in Europe, there are lots of lights with yield or Stop signs…like some posters have mentioned, they are used when they turn off the traffic lights late at night. Unlike in the US, though, where the lights usually go to a blinking red/yellow, they actually turn them completely off over here.
I’ve never seen the sign / light in the states, unless it’s coupled with a constant blinking Red, but I’ve done the vast majority of my driving in Ohio and New York.