Hi, currently stored credentials are not accessible to scripts, they are instead used by the built in DNS API or deployment tasks etc. For your use case would you need access to multiple credentials or just one?
Technically, they are stored in an sqlite database under C:\ProgramData\Certify\credentials and the secrets are encrypted using the windows data protection APIs.
As a workaround you could use an alternative vault (such as Hashicorp vault or Azure Keyvault, or Powershell Secrets Management Module) to store and retrieve the credentials you need for your scripts.