This character is a Other Letter and is mainly used in the Old Italic 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+10309 forms with similar adjacent characters prevents a line break inside it. The glyph can be confused with one other glyph.
The Wikipedia has the following information about this codepoint:
The Old Italic scripts are a family of ancient writing systems used in the Italian Peninsula between about 700 and 100 BC, for various languages spoken in that time and place. The most notable member is the Etruscan alphabet, which was the immediate ancestor of the Latin alphabet used by more than 100 languages today, including English. The runic alphabets used in Northern Europe are believed to have been separately derived from one of these alphabets by the 2nd century AD.
Representations
System
Representation (click value to copy)
NΒΊ
66313
UTF-8
F0 90 8C 89
UTF-16
D8 00 DF 09
UTF-32
00 01 03 09
URL-Quoted
%F0%90%8C%89
HTML hex reference
𐌉
Wrong windows-1252 Mojibake
Γ°ΒΕβ°
Encoding: GB18030 (hex bytes)
90 30 CE 37
RFC 5137
\u'10309'
Bash and Zsh inside echo -e
\U00010309
C and C++
\U00010309
C#
\U00010309
CSS
\010309
Excel
=UNICHAR(66313)
Go
\U00010309
JavaScript
\uD800\uDF09
Modern JavaScript since ES6
\u{10309}
JSON
\uD800\uDF09
Java
\uD800\uDF09
Lua
\u{10309}
Matlab
char(66313)
Perl
"\x{10309}"
PHP
\u{10309}
PostgreSQL
U&'\+010309'
PowerShell
`u{10309}
Python
\U00010309
Ruby
\u{10309}
Rust
\u{10309}
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