Cmdlets related to remoting endpoint configuration, such as New-PSSessionConfigurationFile, are windows-only and not working on unix plats currently. But they are exposed on unix platforms.

If New-PSSessionConfigurationFile and other PSSessionConfiguration related cmdlets are not supposed to work on unix at all, we should not expose it on unix platforms.
If some of its features work on unix, then we need to either if/def the windows-only features or throw a friendly error message when they get used.

For example, RoleCapabilityFiles is only supported on Windows:

New-PSSessionConfigurationFile -Path .\TestConfig.pssc -RoleDefinitions @{
           Administrators = @{ RoleCapabilityFiles = "$RoleCapDirectory\NoFile.psrc" }
}