I needed to free up some space so that I could perform an upgrade.
I had configured backups to be uploaded to S3 a number of months ago, but hadn’t checked for a while.
I was startled to discover that there were apparently no backups for the last three months (approx). I could not check the S3 bucket, but there were none on the local instance.
Oddly, after the upgrade, they have all magically returned.
currently running v2.2.0.beta7 +49.