libgnustep-base1.25 binary package in Ubuntu Bionic amd64

 The GNUstep Base Library is a powerful fast library of
 general-purpose, non-graphical Objective C classes, inspired by the
 OpenStep API but implementing Apple and GNU additions to the API as
 well. It includes for example classes for unicode strings, arrays,
 dictionaries, sets, byte streams, typed coders, invocations,
 notifications, notification dispatchers, scanners, tasks, files,
 networking, threading, remote object messaging support (distributed
 objects), event loops, loadable bundles, attributed unicode strings,
 xml, mime, user defaults.

Source package