The group-symbol-value type indicates how the symbol for a group is indicated in the score. Values can be none, brace, line, and bracket; the default is none.
<xs:simpleType name="group-symbol-value"><xs:annotation><xs:documentation>The group-symbol-value type indicates how the symbol for a group is indicated in the score. Values can be none, brace, line, and bracket; the default is none.</xs:documentation></xs:annotation><xs:restriction base="xs:string"><xs:enumeration value="none"/><xs:enumeration value="brace"/><xs:enumeration value="line"/><xs:enumeration value="bracket"/></xs:restriction></xs:simpleType>