As explained in the front page, LogDistiller is meant to be easily extensible. LogDistiller Extensions Center is a place to develop and publish LogDistiller extensions.
The most common extensions are log types, to adapt to custom log formats.
Other more specific extensions are plugins, to create new features when analyzing log files.
Publishers extensions are here to provide new report format or means of reports publishing.
You can either download them by hand and put in your classpath, or use Ivy or Maven Ant Tasks to automatically download them.