Anonymize user
From MoodleDocs
Template:Moodle 2.0 Anonymize user information is a backup feature in Moodle 2.0 which will "protect user identities" by making each user anonymous. If this box is checked in Backup>Initial settings, Moodle will substitute aliases for real names, substitute @example.com e-mail addresses and so forth.
For example "Max Manager" might become "anonfirstname4 anonlastname4"