Getting the document link of a ComponentSet using Figma API

In Figma, we can give a description and a document link not only to components, but also to sets of component variants.
If a component variant has no document link by itself, then it inherits its parent(the component set)'s link if there’s one.

However, it appears to me that I can only get the document link of an individual component / variant, but not that of a component set via Figma API (https://www.figma.com/developers/api#files-types).

Apparently, the metadata of component sets in a published team library doesn’t include the information either (https://www.figma.com/developers/api#library-items-types).

Is it not supported it at all or is there a way or workaround I can get the information through the current API?