This is not a sample, it is a built until used by the sample.

Tomcat has an Ant based util called txt2html 
(see http://svn.apache.org/repos/asf/tomcat/tc6.0.x/tags/TOMCAT_6_0_17/java/org/apache/tomcat/buildutil/Txt2Html.java).   
This util is only used in tomcat build time and don't seem to be available in a standalone tomcat jar.

This module borrows the Txt2Html.java from tomcat and enables the jsp and servlet samples 
in geronimo to generate html files for source files.