Map on front side bike

Hello, in Ziwft I’ve noticed, while biking, some cyclists with some kind of map (?) on the front side of their bike (have seen some runners too, running with a map in forty of them).
What does this mean?


It means they are doing a workout.

Thanks. It looks like I don’t see it myself doing a workout…

I think you see it if you do a side view

OK, I will have a look next time