What is this for?

[Aparecium]

At the bottom of the door in a toilet cubicle at a service station.

To open the door with your foot.

Maybe so you can pull the door open without using the handle? But you'd still have to use your hand on the lock, so not sure my reasoning stands up.

As above - they appeared in lots of places during lockdown so people didn't have to touch the door and spread Covid.

Did they?

Genius!

But you still have to touch the lock with your hand to unlock it, so what's the point in it?

Does it hook onto the door stopper thingy so that the door stays open so you know it’s free?

No. I actually checked this 🤭