4
when you install or update a module, all the templates for that module are added to the XOOPS database - into the default template set.
To see your changes you'll need to do one of the following:
1. Update the module (system in this case) to add the modified templates to the database
2. Clone the default template set in System -> Templates and make your changes in the cloned template set. Once your changes are made, switch the site template set in System -> Preferences.
Of the two, I prefer to use #2, because that leaves the default templates around in case I mess something up.