Its probably their name for an automated admin task. The post does bot imply that this was merely a checklist of things to do. Ansible calls their automatiin receipts playbook as well.
It's probably a page on the internal Wiki that the S3 team follows for that particular task. Most the actual steps are probably automated, but it sounds more like a checklist.
I used to follow runbooks/playbooks written on the internal wiki when I worked at Amazon.
I don't think it means "playbook" in the Ansible sense. The dictionary (i.e. Wikipedia) definition of "playbook" is "a document defining one or more business process workflows aimed at ensuring a consistent response to situations commonly encountered during the operation of the business", and that's how I know it.
At $work, certain types of frequently-occurring alerts have playbooks that document how the alert in question can be diagnosed and how known causes can be remedied. Something like "Look at Grafana dashboard X. If metric Y is doing this and that thing, the cause is Z. Log on to box 16 and systemctl restart the foo.service."
