This character is a Other Letter and is mainly used in the Gothic 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+10345 forms with similar adjacent characters prevents a line break inside it.
The Wikipedia has the following information about this codepoint:
The Gothic alphabet is an alphabet used for writing the Gothic language. It was developed in the 4th century AD by Ulfilas (or Wulfila), a Gothic preacher of Cappadocian Greek descent, for the purpose of translating the Bible.
The alphabet essentially uses uncial forms of the Greek alphabet, with a few additional letters to express Gothic phonology:
Latin F.
A questionably Runic letter to distinguish the /w/ glide from vocalic /u/.
The letter hwair (Ζ) to express the Gothic labiovelar.
Representations
System
Representation (click value to copy)
NΒΊ
66373
UTF-8
F0 90 8D 85
UTF-16
D8 00 DF 45
UTF-32
00 01 03 45
URL-Quoted
%F0%90%8D%85
HTML hex reference
𐍅
Wrong windows-1252 Mojibake
Γ°ΒΒβ¦
Encoding: GB18030 (hex bytes)
90 30 D4 37
RFC 5137
\u'10345'
Bash and Zsh inside echo -e
\U00010345
C and C++
\U00010345
C#
\U00010345
CSS
\010345
Excel
=UNICHAR(66373)
Go
\U00010345
JavaScript
\uD800\uDF45
Modern JavaScript since ES6
\u{10345}
JSON
\uD800\uDF45
Java
\uD800\uDF45
Lua
\u{10345}
Matlab
char(66373)
Perl
"\x{10345}"
PHP
\u{10345}
PostgreSQL
U&'\+010345'
PowerShell
`u{10345}
Python
\U00010345
Ruby
\u{10345}
Rust
\u{10345}
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