This character is a Other Symbol and is commonly used, that is, in no specific script.
The glyph is not a composition. It has no designated width in East Asian texts. In bidirectional text it is written from left to right. When changing direction it is not mirrored. The word that U+1D158 forms with similar adjacent characters prevents a line break inside it. The glyph can be confused with 2 other glyphs.
The Wikipedia has the following information about this codepoint:
In music, a notehead is the part of a note, usually elliptical in shape, whose placement on the staff indicates the pitch, to which modifications are made that indicate duration. Noteheads may be the same shape but colored completely black or white, indicating the note value (i.e., rhythmic duration). In a whole note, the notehead, shaped differently than shorter notes, is the only component of the note. Shorter note values attach a stem to the notehead, and possibly beams or flags. The longer double whole note can be written with vertical lines surrounding it, two attached noteheads, or a rectangular notehead. An "x" shaped notehead may be used to indicate percussion, percussive effects (ghost notes), or speaking. A square, diamond, or box shaped notehead may be used to indicate a natural or artificial harmonic. A small notehead can be used to indicate a grace note.