TWiki formatting rules (http://twiki.org/cgi-bin/view/TWiki/TextFormattingRules) state that html tags may be included in a Twiki Page. In some cases, this is required to achieve certain effects. See the description of Verbatim Mode, where it says that <pre>...</pre> should be used in certain cases.
However, when running the mvn site on .twiki files, all "<" and ">" are replaced by "<" and ">
Steps to reproduce:
Create a maven site project.
Add a .twiki file with the following content:
---+ Twiki test
After the site has been generated, no <pre> tags will exist instead the following will be shown: