What are Sage 300 ".NET Libraries"?

We are upgrading from Sage 300 2018 to Sage 300 2021.  After installing Sage 300 2021 in our test environment, we ended up with "Sage 300 2021" showing up in the software inventory for that machine, which was expected, but we also now see "Sage 300 .NET Libraries 2021 (version 6.8)" installed.  We did not have a similar product like that with Sage 300 2018.  Is this something new, or is it something that has been around but not separate from the core product?  Can you explain what it does and why it is a separate component?  Is it required for Sage 300 2021 to work? or might it be optional?  If the latter, how does one determine if they should keep it around?