What is this piece called (from the balcony windows)?

Does anyone know what this piece is called?

It’s attached to the lower rail of the balcony window. Last week, during a hot day, my window was stuck shut, and when I finally got it open, this part shifted out of place and a small piece broke off. I’d like to replace it, as it looks like it might break completely soon.

I haven’t been able to find it online. One manual referred to it as a “lower opening hole cover,” but I’m not sure if that’s the correct name.

Any help is appreciated – kiitos! 🙂