I want to know where the document of a Asset-Manager's parameter "Has Blueprints" details. I

I want to know where the document of a Asset-Manager’s parameter “Has Blueprints Classes” details.

You can find “Has Blueprints Classes” in “Project Preference > Asset Manager”.

What dose it do, if it check-box set a true?

I can’t find a document of “Has blueprint” on unreal engine 4.0 documents.