Why multiple solution files for PnP.Core and PnP.SharePoint ?

I am using a lot pnp template provisioning in Powershell. Sometimes I need to do some debugging. For debugging I need to download the PnP Core and PnP Powershell solutions. I see in the recently version in github multiple solution files. I didn't find some documentation about these multiple solution files. Before it was 1 solution file for PnP Core and 1 for PnP Powershell.

Can someone tell me why there are now 2 solution files for PnP Core and 2 solution files for PnP Powershell? Both solution files have their own file structure.