You may see the labels "internal" or "external" on metrics, checklists, and projects.
In fact, you might also see the drop-down menu to the upper right of the section that lets you view just internal, just external, or both.
To understand what those mean, you'll need to know where you're viewing the item.
If you're on a circle page, internal items are ones that only exist inside the circle. They are reported in that circle's Tactical meetings, and are held by roles inside the circle.
Conversely, external items are ones that are assigned to the circle itself. They will show up in the super-circle's Tactical meetings, but they will not show up in the meetings of the circle itself.
However, if you're viewing them from the role page, you're likely to see only external items. That's because they are external to the role, in that they exist in the broader circle and interact with the meetings there.