User groups can be added to other user groups, which is called nesting. To each user group, you can add up to five user groups in depth. All nested user groups get access to the applications the top user group is subscribed to.
‘Direct users and user groups’ were added directly to the user group you are viewing, and they get their application access from this user group.
‘Expanded users’ means both ‘direct user and user groups’ and the users and user groups that have access from the user group you are viewing because the user group they belong to was nested in this user group.