Visual Interface Builder for GNUstep

 Gorm, the GNUstep Object Relationship Modeler, is a tool to build GUI
 interfaces for the GNUstep system. It is a clone of the NeXTStep
 "Interface Builder" app. It works well with ProjectCenter to create
 GUI applications for GNUstep.
 .
 You can create .nib files that also work on macOS and vice versa.