Template name comments should be included in designer mode

[Colonel_mortis]

In dev mode, you add a comment to the top of each template identifying what it is, which is really useful for figuring out what's causing things to happen or where to hook. It would also be really useful in designer mode, because it would allow the designer to figure out which template they need to edit, rather than having to dig through files to find the relevant one.

[Daniel F]

This was included in 4.1.16.
To active this, you have to put

define('DEBUG_TEMPLATES', TRUE );

into your constants.php file