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+1D15C forms with similar adjacent characters prevents a line break inside it.
The Wikipedia has the following information about this codepoint:
In music, a double whole note (American), breve (British) or double note lasts two times as long as a whole note (or semibreve). It is the second-longest note value still in use in modern music notation. The longest notated note is the longa, which could be double or triple the length of a breve, although its use is most commonly found in early music. The longest notated note (though now obsolete) is the maxima.
Representations
System
Representation (click value to copy)
NΒΊ
119132
UTF-8
F0 9D 85 9C
UTF-16
D8 34 DD 5C
UTF-32
00 01 D1 5C
URL-Quoted
%F0%9D%85%9C
HTML hex reference
𝅜
Wrong windows-1252 Mojibake
Γ°Ββ¦Ε
Encoding: GB18030 (hex bytes)
94 32 C4 36
RFC 5137
\u'1D15C'
Bash and Zsh inside echo -e
\U0001D15C
C and C++
\U0001D15C
C#
\U0001D15C
CSS
\01D15C
Excel
=UNICHAR(119132)
Go
\U0001D15C
JavaScript
\uD834\uDD5C
Modern JavaScript since ES6
\u{1d15c}
JSON
\uD834\uDD5C
Java
\uD834\uDD5C
Lua
\u{1D15C}
Matlab
char(119132)
Perl
"\x{1D15C}"
PHP
\u{1d15c}
PostgreSQL
U&'\+01D15C'
PowerShell
`u{1D15C}
Python
\U0001D15C
Ruby
\u{1d15c}
Rust
\u{1d15c}
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