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."