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+04E8 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:
Oe or barred O (Ө ө; italics: Ө ө) is a letter of the Cyrillic script.
Representations
System
Representation (click value to copy)
Nº
1256
UTF-8
D3 A8
UTF-16
04 E8
UTF-32
00 00 04 E8
URL-Quoted
%D3%A8
HTML hex reference
Ө
Wrong windows-1252 Mojibake
Ó¨
Encoding: GB18030 (hex bytes)
81 30 E2 30
Encoding: KZ1048 (hex bytes)
A5
Encoding: PTCP154 (hex bytes)
A4
LATEX
\cyrchar\CYROTLD
Adobe Glyph List
Obarredcyrillic
RFC 5137
\u'04E8'
Bash and Zsh inside echo -e
\u04E8
C and C++
\u04E8
C#
\u04E8
CSS
\0004E8
Excel
=UNICHAR(1256)
Go
\u04E8
JavaScript
\u04E8
Modern JavaScript since ES6
\u{4e8}
JSON
\u04E8
Java
\u04E8
Lua
\u{4E8}
Matlab
char(1256)
Perl
"\x{4E8}"
PHP
\u{4e8}
PostgreSQL
U&'\04E8'
PowerShell
`u{4E8}
Python
\u04E8
Ruby
\u{4e8}
Rust
\u{4e8}
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