I've finally figured out where to edit the
MYCode Guide that provides text examples of how to do all the special formatting.
They don't make it easy to find and modify (unless there's a "Read Me" file somewhere I overlooked).
So now when you click on that link, the top section shows you the default MyCode markups you can use in your Posts and if you scroll down you'll see the custom/bespoke MyCodes we've implemented here on SF-Fandom (less a few I think are outdated).