Plugins are mainly user-contributed add-ons that enhance and extend TWiki features and capabilities. A limited number of plugins are included in the core TWiki distribution - and most those can be removed - while the rest are optional, available from TWiki:Plugins/WebHome.
Here is a list of the plugins currently installed on this TWiki site:
DefaultPlugin: This plugin can be used to specify some simple custom rendering rules. It also renders deprecated *_text_* as bold italic text.