I have some questions about the em-mail layout for the system emails in the CMS.

There are some settings like a logo we can add to the template. But there are no options to set the footer color or maybe disable the copyright line?

When I want those changes I probably need to need to override this file?

layouts/joomla/mail/mailtemplate.php

In the options for the email templates there is a 'layout' option that only contains '- Use default - '. So is there a setting somewhere to set the default? Can we add our own custom template? I tried adding a custom file to layouts/joomla/mail/ but it did not show in the layout options.