Does anyone know what this green sponge is on a friend of mine's 1.3 Fiesta?

Does the pipe go to the airbox? If it is could be a breather filter.

That would make sense. And that filters the oil fumes from the air intake, is that right?

Sadlo is right, its to stop particles and only let blow by gasses through.

That's correct, it is supposed to stop oil from entering the airbox from the crankcase.
The ST has one too but its in the airbox and its a black sponge.

Thanks all