If I have 100 users assigned to a to-level modern folder, is there a way to limit the number of users in a sub-folder? Can I break the user inheritance? Is that what the “View Inherited Users” checkbox does?
Sub-Folders inherit from their Parent, If you wanted to separate the permissions I believe you’ll either need to create multiple top-level/root folders or only assign users/groups in the sub-folders where they are needed.
The “View Inherited Users” does just that, it displays the users that have inherited permissions from the parent folders. If you assign everyone in top-level A and assigned nobody in sub-folder B, and unchecked that box, the view of users should be empty.