PowerShell v3 introduced CDXML modules. Cmdlet Definition XML wraps a CIM class in XML to create a module. The methods of the CIM class can be used to generate additional cmdlets for the module. Many of the modules introduced with Windows 8 – including the networking and storage modules – are created in this manner though producing modules in this manner hasn’t caught on with this concept. The PowerShell 6.x releases didn’t check the XML of the CDXML modules against the CDXML schema as the required APIs weren’t available in .NET core 2.0. The APIs are in .NET Core 3.0 and the CDXML schema checks are built into PowerShell 7.
under: PowerShell 7