Email asset does not show which template it was built on and shows the word "none" instead of the name of the template that was used to create that asset.
Any edit directly to the HTML code of an email will break the connection between the email and the template. Changes made to the template will no longer flow down to the email. After making those change you will see a template name of None instead of the name of a template.
When editing the HTML in the email, you will see this warning message: