I've been struggling to implement a more complicated version of the example from Acer here:
The basic idea is that Maple allows XML for typesetting (and maybe MathML? I don't use the MLs, so I can't speak to limitations or differences).
It's somewhat straightforward, but extremely tedious. The statement that this is " undocumented, but not overly difficult " may be true, but it's time-consuming to learn bits and pieces of any additional language just to typeset something that resembles extremely common typesetting language, and frankly feels like a waste of time. In a world where we have LaTeX, I don't see why Maple can't use LaTeX language for typesetting in plots. Python, MatLAB have this feature, and a homebrew version of this for Mathematica came up during my searching, but nothing useful for Maple. The Physics package has some function to take the Maple and produce LaTeX code (untested by me so far), but not being able the other direction to typeset axes, titles, and textplots with LaTeX notation is shocking to me.
When one attempts the tag formating from html/XML like here:
or formatting, errors come up. Basic things like having control over a given character's size seem impossible without the tag formatting, and I tried for some time to get all sorts of variations of #mstyle to work using the syntax method of the linked question. The converters that I've found that go from LaTeX to MathML use this tag formatting.
Here are some examples that I made up to demonstrate acer's method and one particular area where the MathML spectactularly fails compared to LaTeX, and included to (current as of this moment) links that give element names for XML and symbol names for html/xml:
The contents are failing to be inserted, but the file downloads correctly from the preview for me.