Forthcoming update to the C# language extends params parameter support and introduces a new type that supplies extension members for an underlying type.

Take advantage of nullable types to assign 'no values' or 'null values' to value types when there is no value available The C# language provides support for two types of data: value types and ...

The announcement of the future addition is related to Extension types which in C# 13 will be expanded by providing additional methods, properties, and members to underlying types.