If I understand the proposal correctly, it works like a stack.

So you're working on "git plan --commit-message='important feature'" or whatever the syntax would be.

Then you encounter a place where some refactoring would be really helpful, so you do

"git plan --commit-message='refactor: ...'"

Any changes made during this plan won't show up in the original git plan.

I'm not sure if this is how it works, but that's how I understood it.