There's no dedicated page in the docs on this subject. We could certainly consider adding one in the new documentation site (currently in the process of being set up).
The documentation should point out what I have often said, which is that we have little control over how AsciiDoc is rendered on GitHub and, at best, the rendering should be considered an adequate preview, not a publishing target. We're at the mercy of GitHub's decisions and commitments. They have decided to disable certain features (like the include directive), have denied the request to add integrations like Asciidoctor Diagram and STEM support, and have resisted changing styles to get things like text alignment and floats to work. We can't do anything about that (other than to continue to plead with them).
In contract, you'll find that GitLab has been willing to do all of these things. So it's certainly possible. But again, it's up to the maintainer of the platform.
On Wed, Nov 11, 2020 at 5:48 AM oddhack [via Asciidoctor :: Discussion] <[hidden email]
Github's built-in asciidoctor renderer seems to ignore :stem:, and I gather that it doesn't support include directives either, but despite considerable searching I haven't been able to find anything documenting just what all the restrictions are. It would be very helpful for our needs if there were a way to get latexmath or even just asciimath markup working via github, in case anyone has done this.