DSC is a configuration management tool that first appeared in PowerShell v4 and was refined in PowerShell v5/5.1. Major changes are coming to DSC of which more later. DSC takes a configuration and applies it to a server. What about the situation where you have an existing server and want to derive a DSC configuration for it. Various home grown methods have been discussed at the PowerShell Summit, amongst others, but now we have Reverse DSC – https://blogs.technet.microsoft.com/heyscriptingguy/2017/10/27/reverse-desired-state-configuration-how-it-works/
Reverse DSC is available for SharePoint, SQLServer, RemoteDeskTopSession and PSDesiredStateConfiguration. You do need the required resource module for Reverse DSC to work.
Reverse DSC uses the Get functions of resources to get the configuration information.
You get get hold of Reverse DSC, and contribute, at https://www.GitHub.com/Microsoft/ReverseDSC