In DNN 7 at least the default is 'change.me'.  I have just spent almost a week trying to find out why pre-loaded users could not request a password during login.  The system told the users an email had been sent but none ever arrived. Emails from the Events module were successfully delivered.  I believe the problem was caused because 'change.me' is not a valid email format. Something like 'change@me.now' or 'now@change.me' would have sent the email.  I fixed this by changing the Administrator in SiteSettings > Advanced Settings from host to someone with a valid email address