Github by default renders asciidoc admonitions (e.g. WARNING, IMPORTANT, CAUTION) as plain text instead of the typical icons. When our adoc files get converted to html, the Asciidoctor Maven Plugin inserts the usual icons in the html, which is the key thing, but when we look at the docs source in github we don't see them.
https://gist.github.com/dcode/0cfbf2699a1fe9b46ff04c41721dda74#admonitions explains how to fix this. Basically the following metadata in the top level docs:
Most, perhaps all, of our docs already have ifdef::env-github blocks so this is just a matter of adding a few more directives.