Default email text
If you have modified an email template you will see a return arrow button has appeared next to the save button, and the icon in the list is dark instead of light.
Clicking the return arrow will reset the template to the default.
Unless you have another organisation above yours with a customised template (in which case you will get that instead) those defaults are:
Account created (activation)
Account moved
Account expiring
Account created (password)
Password change confirmation
Reset password
Anything to watch out for?
If you are in a hierarchy and the organisation above you has customised the email template, the return to default button will use that customised template as your default