Column type 0x20 and 0x21 unspecified, but returned by AWS-based SQL Server instances

Specifically on SQL Server running on AWS as service, there is a column type 0x20 and 0x21 being returned. On other SQL Server editions (on-premises, Azure) this has not yet been found in identical scenarios.

Wireshark TDS seems also unable to handle it, leading to nonsense column metadata being reported.

The documented types are listed in 2.2.5 Data Type Definitions.

Is it possible to add documentation and logic in C# how to interprete these column types 0x20 and 0x21 as part of the TDS specification to allow building a custom SQL Server client?

TDS column type 0x20

Reproduction: start SQL Server Management Studio and connect to SQL Server on AWS. First statement is:

With result for the first column (a non-casted 1 as value) a column data type 0x20:

TDS column type 0x21

Reproduction: run a query returning 1 cased as tinyint/shortint/int (always 0x21):

Resulting data type for column according to SQL Server instance is column data type 0x21:

Start by comparing the TDS type definitions in section 2.2.5 with the existing C# handling of column metadata. Reproduce 0x20 with a non-casted 1 and 0x21 with the tinyint, shortint, or int queries against SQL Server on AWS. Done means the two types' semantics are documented and handled well enough for a custom TDS client.