That was my reaction too. It took me a few seconds to realise I was looking up at the dome lights, and the object half-visible in the bottom of that image is the rearview mirror. This video confirms it:

https://www.youtube.com/watch?v=zIBMxGdbjfo

On every other car I've been in, any switches in that location I would naturally assume are for controlling the lights right next to it, but evidently no one in Tesla's design chain thought of that...