Question

At skill catalog, how to understand which skills belong to framework skills?

Answer

In the skill catalog, hover the cursor over the skill description, and it usually tells that the skill was trained on a small set of documents if it is a framework skill.


Also, the information which built-in skill is a framework one can be found in the Help:

EU region: Skill Catalog Guide > Built-in Skills

US region: Skill Catalog Guide > Built-in Skills