Draw an Offset curve

I want to inline some geometric shapes. I found offset curve in the help, but I don’t think it’s meant to help me draw a glyph, right?
Hence my question: If I draw a closed shape, how do I create an inline or outline? In Illustrator this works via “Offset Path”. Is there a similar filter / function in the glyphs editor window in Glyphs?

There is a Make stroke option in the offset path filter.

And that might help:

After I changed the language, I found it immediately.
One question: When I use Offset Curve, the selected object changes. Is it also possible to add the path as a “copy” so that the selected object is retained and I have two paths? For example, if I have a rectangle to which I want to an have an in- or outline.

You can do that in a second layer or second master, depending on what you want to do. If you are planning a color font, consider a color layer as described in the color font tutorials.

If set the position to 0% or 100%. That will keep the original outline.