Kirigami.Separator draws a line. It would be nice if we could get a version that's just 18px tall (i.e. gridUnit) of whitespace. Sometimes instead of a line you just want a bit of whitespace! This is what we use for QWidgets-based FormLayouts, such as the ones used in Dolphin and Spectacle's settings windows. It would be nice to make a Kirigami version of this for greater visual consistency.
Talked to Marco and found out this is not actually needed.