SVG layers in Glyphs 3

I can make an SVG layer in Glyphs 2 by naming it “svg”, and it will persist when the file is opened and saved in Glyphs 3 with Glyphs 3 file format.

But how to make such layer in Glyphs 3 directly? When I name a layer “svg” there, no special handling seems to be applied. When I drag an SVG file into it, paths are imported instead of placing the SVG as an image.

The layer type is set from the context menu (just like the brace and bracket layers). But the svg setting was missing from the menu. I fixed it. For now, you can use this script:

Layer.attributes["svg"] = True