A routing effort might be a combined hand-routing vs. external auto-routing. Let's call these 'routing sessions'.
It should be possible to tag each session with a name to be able to individually rip-up parts done in different sessions. That way it is possible to 'try out' something with an auto-router but then rip-up only that part again. Or stash them away to try out various ways manually so that it is easy to go back to a particular effort. Essentially undo/redo that combines a number of tasks.
A routing effort might be a combined hand-routing vs. external auto-routing. Let's call these 'routing sessions'. It should be possible to tag each session with a name to be able to individually rip-up parts done in different sessions. That way it is possible to 'try out' something with an auto-router but then rip-up only that part again. Or stash them away to try out various ways manually so that it is easy to go back to a particular effort. Essentially undo/redo that combines a number of tasks.
Should be possible to store in the file as well.