I have a 3D Sketch in a subassembly. It was made to rough sketch a proposed change. It was not used in any way to actually place or define any component, let alone any features in components.
All I wanted to do was delete it because it has served its purpose. Sure, I can just hide it instead, which I have done. This isn't stopping me in any way.
I do wish to understand how I would be able to find which things need changed to remove Freeze, if I needed to.
Here you can see that it has references in source but not in destination or propagated references forward.
Install reference 2018 SP5.