It is a heavily simplified (150 lines of code) version of HT-AJAX that is compatible with newer versions (>1.1) of HUNCHENTOOT. It was initially developed for GTFL and therefore provides only one type of Ajax processor (which resembles the 'simple' processor of HT-AJAX).
It's provided by Martin Loetzsch and can be found at http://martin-loetzsch.de/ht-simple-ajax
web framework