Some little DAB/DAB+ and DVB-T/DVB-T2 (with HEVC) receiver module which you plug into the microUSB port at the bottom on your phone. It should be smooth with the Fairphone shape, so the width is 73 mm and the thickness 11 mm. Also, it should have some microUSB connector at the bottom to charge your phone even with the receiver module.
So you can save your mobile data when you watch TV or listen to a non-FM radio station.
Well, I currently don’t need such a module. (Well, this need could come in some time. For example, before two years, I had no need for a smartphone and now, I finally bought a Fairphone 2.) But I think there could be some people who have the need for it. Especially the football junkies who want to watch the games live.
Do you mean a module which you connect to your satellite dish and then you watch TV?
This can also be done by some app, especially if you think of a little piano, for those who don’t want to take a “hardware piano” with them.