I've favourited a few questions that later get closed as duplicates, merged, and eventually deleted. I can find the "better" target question because I can see the deleted question, and find where the content went, but I shouldn't have to rely on this.
Formal specifics:
- If I've favourited a question, and it gets closed as a dupe, please add to my favourites list all the questions that are marked as duplicates
- When it is merged into another question, please add to my favourites list the question it was merged to