gavinsmith Flarum is an awesome feature-rich forum but it seems a bit odd to have to install an "extension" to manage the user list!
Most of the Flarum features are actually extensions, it's just that many of them are developed by the Flarum team and bundled with Flarum when you install it. For example, the like button or the ability to reply to posts or mention users is achieved through extensions. The great thing about that is that if you want to remove a feature or replace it with your own adapted version you can do that very easily.
For the users list, there's currently no core extension for that, so yeah, you need to manually install a third party extension for that.
gavinsmith One more question: "View user last seen time" in the Dashboard Permissions. Where do I see that information?
In the profile page of a user.