The Anonymous user has been granted Administer access. While this is the default, "out of the box" configuration for on-premise installations of ProGet, this is intended for demonstration purposes only and you should adjust the below configuration to properly secure your instance.

Task Scope Users & Groups
Administer all feeds AdministratorsAnonymous
Manage Feed No principals have permissions or restrictions for this task.
Promote Packages No principals have permissions or restrictions for this task.
Publish Packages No principals have permissions or restrictions for this task.
View & Download Packages all feeds Anonymous