http://hobbes.nmsu.edu/cgi-bin/h-search?key=gx-
This is a native 32-bit OS/2 XML editor and parser; it can do full validation and SGML compatibility checking. The editor uses document type definitions to provide guidiance in authoring correct documents. For example, use it to create HTML 4.0 documents, or DocBook books and articles.
Source: OS2 Warp News and Rumors