Does outdoor temperature sensor need to be connected to something?

I’ve lived in a Persimmon new build house for 8 years and only just noticed that on the exterior rear wall there’s a circular grey plastic box that’s not connected to anything, but the neighbours all have a cable coming out and going into the wall. The writing on the outside is Honeywell so10076 and google tells me it’s an outdoor temperature sensor. What does it do and does this need to be connected or not? Thanks