Work done in #4125 to eliminate manual props info tables for complex components highlights room for improvement in documenting generic types:

EuiBasicTable makes use of cascading generics to typeitems, but this is not immediately clear in the docs, nor is it clear what shape T can take.

Updates should include some clearer indication that a type is generic, and some documentation about the default value, extension, or shape of the generic. It could be that we are limited by react-docgen-typescript.