Revit Lookup is a great (and free) tool to learn more about what’s in your Revit models. If you want to look at source code, deal with GitHub, and learn more about it, go to https://github.com/jeremytammik/RevitLookup
If you just want to install it for Revit 2017-2020, go to https://drive.google.com/open?id=1lnhx9ngyTZHi-hMMby-4a5K8NyWIFtV5