Posted by rockyallen on Aug 17, 2017; 9:51pm
URL: https://discuss.asciidoctor.org/Asciidoctor-pdf-Custom-admonition-icons-tp5850p5851.html

I don't think it can be done in the yml (though I am happy to be proved wrong). Do it in the Asciidoc source instead by setting attributes icons, iconsdir and icontype.

http://asciidoctor.org/docs/user-manual/#attribute-catalog