I want to free up some space in my btrfs filesystem by deleting some snapshots. But I cannot work out which ones would be effective to delete. This question's answer explains how to show the amount of data held exclusively in one btrfs snapshot. But that doesn't help if your tentatively-deletable data was held for longer than the interval between snapshots. For example, if I create a file on Monday, do daily snapshots, and then delete it on Wednesday, that file will be used by two snapshots, and hence not exclusive to either.
What I think I'm looking for is a way to enumerate groups of snapshots that hold data held by no other snapshots.