How to check if default mail template (ntf) is modified / changed

I would like to know how to check if the default mail template were already modified / changed?Are there any specific checking, or are there only setting in the database if it was already modified by a user.

Please advise.

Subject: Check the signer of the different design elements.

The only way I think that could be done is to go through all design elements and check if any have been signed by a different person.But you should not allow regular users to edit templates, that should only be done by the designated developer, and he/she should keep a change log of every design element that was modified , and what was done.