Confirmation email form

The option “E-Mail-confirmation” after a registration is active.
New registered users get these emails:

To activate your user, please click the following link:
https://etc.
After you activate it you will receive yet *another email* with your login.

And:

Welcome to the Forum!
Your username is: <name> and your password is the one that you have selected during registration.
Access your account: https://etc.

I have to change these forms a bit and translate them, as the site is in German.
But where are these forms?
I’ve searched for hours now and cannot find them.

The page I need help with: [log in to see the link]