I'd like to customize the registration email template in 2.6 beyond just changing the language file.  I'd like to display additional information (site URL prominently displayed  in the body instead of hidden in the footer for example). 

I have looked at UserAdvManager and I could use it but on registration it sends out an additional email besides the one that Piwigo sends for registration.  If I could turn off the default Piwigo registration email,  maybe I could use the UAM plugin since it seems to have some options built in for customizing the templates.  Otherwise I think it's confusing for the users, redundant and a little overkill for what I want. 

Where are the templates located in 2.6 and is editing them the recommended way to go for making extensive changes to the registration email?