As of this writing, the most reliable source is the page. The System CLR Types are part of that feature pack.

This is the most common reason for a manual download. The Report Viewer cannot function without these types, as it uses them to render reports that might contain spatial or hierarchical data.

You might have a web server (IIS) that communicates with a separate SQL Server machine. Even though the SQL Server engine is on another machine, your web server needs the CLR Types library to process the data locally. This "Feature Pack" download is designed precisely for these "client-only" scenarios.

: Can be installed on client machines or web servers without requiring a full SQL Server instance, allowing applications to use SQL types natively. Performance