Your Joomla System plugins operate every time a page on your site loads - which is typically when a visitor visits a page on your website.
These System Plugins control your URLs (Universal Resouce Links), whether users can tick (select) a "Remember me" box on the Login module, and whether website caching is enabled.
New is the redirect plugin that together with the redirect component will assist you in managing changes in URLs.
Joomla System Plugins have a default state of On for the following:
- Remember me
Where SEF = Search Engine Friendly, and debug is used for debugging your Joomla website.
And a default state of Off (disabled) for the following: