CodeEditor is an attempt at creating a code editor for GNUstep. The grand plan is to use it as a component in ProjectCenter, and also as a stand-alone application.
The hompage link is (still) dead but the mirror link works. The subject of CodeEditor has also been discussed in ImplementSyntaxHighlighting
Apparently the new home of the code is http://savannah.nongnu.org/projects/codeeditor