The GetActorTransform gives you the (local-to-)world-transform of that actor
When you invert the transform you’ll get the inverted world-transform (world-to-local)
This transform would then transform from world-space to local-space of that actor.
The tool-tip is only correct when using an actors transform, you could make your own transform, or combine transform and still use it, but it’ll just return the inverse of that transform, not necessarily a world-to-local
I guess checking out some videos on linear algebra/matrices could help