How does the "Send to shopping list" sync work?

From the planner tap Send to shopping list. Every ingredient from every recipe you've planned that week is added to your shopping list — duplicates are merged (two recipes needing 100g butter become one 200g row), pantry items are silently skipped, and leftover slots are excluded (see the Leftovers FAQ). If you later swap a recipe on the planner, the old ingredients are silently swept off the shopping list and replaced with the new ones — no manual clean-up needed.