explained… The Optimized Storage window
1 Recommended changes
The window opens to this page, suggesting some key ways you can save on storage space.
2 Additional categories
Several items on the left detail space used by various apps, which you might want to reclaim.
3 Message attachments
This category lets you turn on auto-download of only recent attachments – or none at all.
4 Monitor progress
The window needn’t remain open, as you can simply reopen it to check lengthy tasks’ progress.