The numeral-alter element represents an alteration to the numeral-root, similar to the alter element for a pitch. The print-object attribute can be used to hide an alteration in cases such as when the MusicXML encoding of a 6 or 7 numeral-root in a minor key requires an alteration that is not displayed. The location attribute indicates whether the alteration should appear to the left or the right of the numeral-root. It is left by default.
The
<numeral-alter>element.The numeral-alter element represents an alteration to the numeral-root, similar to the alter element for a pitch. The print-object attribute can be used to hide an alteration in cases such as when the MusicXML encoding of a 6 or 7 numeral-root in a minor key requires an alteration that is not displayed. The location attribute indicates whether the alteration should appear to the left or the right of the numeral-root. It is left by default.
See
https://www.w3.org/2021/06/musicxml40/musicxml-reference/elements/numeral-alter/