What does "no styles applied" actually mean in Style Manager?

Hello! I am working on cleaning up the styles on our current site. In the Style Manager, I am seeing what I think are Combo classes (nested classes with a “+” to the left of them). When I hover over some of those sub-classes, I see a tooltip that says “no styles applied”, which to me would indicate that the class isn’t actually doing anything. However, when I go to the element where the class is being used and try to remove that class, I run across one of three scenarios:

  • I remove the class successfully and the style of the element doesn’t change.

  • I remove the class but the style of the element changes, so it is obvious that the class is doing something.

  • I discover that it’s not the class that said “no styles applied”, but rather its parent class that is an “empty class” and therefore not affecting the element (even though the parent class does NOT say “no styles applied” when hovering in the style manager.

Am I misunderstanding what “no styled applied” actually means? Is there an easier way to clean up these styles? Just to note - these are not “unused classes” and therefore are not affected when I use the Cleanup function in the Style Manager.