Performance style

Please forgive me if this is not the right channel for this question. I'd
appreciate being directed as needed.

I am working on Web-based rendering and automated playback of lead sheets,
and I'm using MusicXML as the main interchange format between various apps
(for notation, conversion, display, playback).

A typical lead sheet contains hints regarding the style of performance,
e.g. Ballad, Bossa Nova, Funk, etc. Also typically, playback engines such
as iReal Pro, Band-in-a-Box and others are able to convert this information
to a multi-track accompaniment to the notated music.

It would seem MusicXML does not include a metadata element to convey the
performance style. Is this correct? Anecdotally, iReal Pro converts their
sheet style to a "creator lyricist" element, to ensure it displays in the
expected place when imported.

But really, what's needed is an explicit element type that can be
machine-read. Ideally, it would be an element that attaches to a timed
event, to allow the style to change over the course of the performance.

Happy to discuss more via a GitHub issue if there's any interest.

Thanks,
Karim