u/Educational-Can6617

A small plastic/rubber cover has come off near my front derailleur on my TT bike and I can’t figure out where it’s supposed to go. The bike still shifts fine, but the little piece is now dangling on a small tether/wire.

I’ve attached photos — does anyone know what this part is called and where it clips back in?

Bike has Shimano Ultegra front derailleur.

Thanks!