libgnustep-gui0.29 binary package in Ubuntu Lunar amd64

 The GNUstep GUI library is a powerful library of graphical user interface
 classes written completely in the Objective-C language; the classes are
 based upon the OpenStep specification, and provide the user with a
 traditional nextstep-like look and feel. The classes include graphical
 objects such as windows, menus, buttons, text fields, popup lists, browsers,
 scrollviews, splitviews, fonts, colors, images, events, pasteboards...
 You need the corresponding backend library package (gnustep-back) to use
 this package.

Source package