U+1D1D0 Musical Symbol Gregorian C Clef

The Wikipedia has the following information about this codepoint:

A neume (; sometimes spelled neum) is the basic element of Western and some Eastern systems of musical notation prior to the invention of five-line staff notation.

The earliest neumes were inflective marks that indicated the general shape but not necessarily the exact notes or rhythms to be sung. Later developments included the use of heightened neumes that showed the relative pitches between neumes, and the creation of a four-line musical staff that identified particular pitches. Neumes do not generally indicate rhythm, but additional symbols were sometimes juxtaposed with neumes to indicate changes in articulation, duration, or tempo. Neumatic notation was later used in medieval music to indicate certain patterns of rhythm called rhythmic modes, and eventually evolved into modern musical notation. Neumatic notation remains standard in modern editions of plainchant.