Hello Lucas Kuiper,
As you asked for document related to Parameters below is the one which discusses on the same.
Quickstart: Create policy assignment using Azure portal - Azure Policy | Microsoft Learn
If you're seeing multiple or confusing parameters (like repeated "Include Arc connected servers"), it may be due to nested policy definitions or initiative-level assignments where each policy has its own parameter set.
To know more about the Azure Policy & Azure Definition look into the below document.
Overview of Azure Policy - Azure Policy | Microsoft Learn
Azure Policy glossary - Azure Policy | Microsoft Learn
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Thanks,
Siva shunmugam.