No worries!
For the future (and just the reference itself):
Trigger based Notifications are being sent via the mail address defined in the group (if not set, it won’t be sent). These mail addresses rely on E-Mail-Accounts configured.
All agent notifications (new ticket, updated ticket, etc) and also system notifications like “password resets” are being sent via the system address which is it’s own channel (out only). This can either be sendmail or smtp depending on what you need. 
I’ll have a look at the docs later on and will check if we can enhance these parts to make that clearer to help further in the future.