Thanks for replying, Stefan. Your tutorial is a really great reference!
However, l still cannot find anything that describes how to achieve what I am thinking. I would like to have some text under a section header that describes the properties within the section – like a label that is not attached to any properties. Here is a mockup of the idea:
I think it would be useful to have a "description" property for a section header in addition to the "label" property.
Sorry for the confusion. I just meant that having a brief description for an extension's properties under a section heading might improve the user experience. It would be easier for a new user to learn how to use an extension quickly if a few hints were provided in the accordion menu.