**timeSigCombNumerator** and **timeSigCombDenominator** are control characters
designed to be combined with the time signature digits (by way of glyph
substitution, such as OpenType ligatures) to shift them vertically into
position suitable for drawing as the numerator and denominator of a time
signature. These control characters are intended for fonts to be used in
text-based applications, since scoring applications should position the
numerator and denominator of time signatures independently.
