Turns out that all of this stuff has apparently been deleted from the official docs some time ago, so that's probably why you didn't find it :) (see sibling comment).

When I did a quick google to pull up the docs that I knew I had read when I implemented the mysql client I found & linked you to a non-official, old copy of the mysql docs from back then.

You can still find the docs for COM_QUERY result on the net though: https://github.com/cwarden/mysql-proxy/blob/master/doc/proto...