System
System plugins operate every time a page on your site loads. They control such things as your URLS, whether users can check a "remember me" box on the login module, and whether caching is enabled.  New in 1.6 is the redirect plugin that with the redirect component assist you in managing changes in URLs.
Default on:
- Remember me Help
- SEF Help
- Debug Help
Default off:
- Cache Help
- Log Help
- Redirect Help
Editors-xtd
These plugins are behind the buttons found beneath your editor. They only run when an editor plugin runs.
Default on:
- Editor Button: Image
- Editor Button: Readmore
- Editor Button: Page Break
- Editor Button: Article
Default off:
- None
Editors
Editors are used thoughout Joomla! where content is created. TinyMCE is the default choice in most locations although CodeMirror is used in the template manager. No Editor provides a text box for html content.
Default on:
- CodeMirror Help
- TinyMCE Help
- No Editor Help
Default off:
- None
