Although I can't help you find more documentation, I can tell you how to find out what you have available.
asciidoctor attributes map to CSS class names. You can see all of the default asciidoctor classnames in the default asciidoctor.css file, which on my system is /usr/local/Cellar/asciidoctor/2.0.9/libexec/gems/asciidoctor-2.0.9/data/stylesheets/asciidoctor-default.css.
The location of your default may be different, depending on where you installed asciidoctor. When you search in that file, you can see entries such as .
On Mon, Jul 29, 2019 at 12:14 AM Mark S [via Asciidoctor :: Discussion] <[hidden email]> wrote:
I have discovered that I can center a paragraph like this: