The interchangeable type is used to represent the second in a pair of interchangeable dual time signatures, such as the 6/8 in 3/4 (6/8). A separate symbol attribute value is available compared to the time element's symbol attribute, which applies to the first of the dual time signatures.
The
<interchangeable>element.The interchangeable type is used to represent the second in a pair of interchangeable dual time signatures, such as the 6/8 in 3/4 (6/8). A separate symbol attribute value is available compared to the time element's symbol attribute, which applies to the first of the dual time signatures.
See
https://www.w3.org/2021/06/musicxml40/musicxml-reference/elements/interchangeable/