Moving folders · Rules and Auto Rules
What's the difference between Default & Manual Rules and Auto Rules?
Short answer: Default & Manual Rules are the baseline for every Mac plus any rules you add, and the optimiser never changes them. Auto Rules are generated for your Mac from its apps and caches, and you can fine-tune their ages. Both live in Settings → Rules.
The rule book in Settings → Rules has two sections. Default & Manual Rules is the baseline that fits every Mac plus anything you add yourself — the optimiser never touches it. Auto Rules are the ones Storage Studio generated for your Mac from the apps and caches you actually have, where you can fine-tune how old something must be before it's cleaned.
Keeping them apart means Storage Studio can keep improving its own suggestions without ever changing a rule you wrote.