Help for DocumentEncryptionCert dynamic parameter is missing
There is no help content for the Document EncryptionCert dynamic parameter of Get-ChildItem.
Because this dynamic parameter is added by the Certificate provider, it should be documented in the <providerHelp><cmdletHelpPaths> section of Microsoft.PowerShell.Security.dll-help.xml.
June Blender commented
It's still missing from custom cmdlet help for Certificate drive as of December 8, 2016