Plesk Onyx 17.8.11 has accessKeyId and secretAccessKey fields that are related to an Amazon AWS Firehose component. NOTE: the vendor's position is that there is no security threat.
https://talk.plesk.com/threads/why-in-plesk-firehouse-aws-keys-are-public.369925/
https://docs.aws.amazon.com/IAM/latest/UserGuide/security-creds.html