This character is a Nonspacing Mark and is mainly used in the Pahawh Hmong script.
The glyph is not a composition. It has no designated width in East Asian texts. In bidirectional text it acts as Nonspacing Mark. When changing direction it is not mirrored. U+16B31 prohibits a line break before it.
The Wikipedia has the following information about this codepoint:
Pahawh Hmong (RPA: Phaj hauj Hmoob [pΚ°Γ’hΓ’umΜ₯ΙΜΜ], Pahawh: π¬π¬°π¬π¬΅ π¬π¬Άπ¬ π¬π¬£π¬΅[pΚ°Γ’hΓ’umΜ₯ΙΜΜ]; known also as Ntawv Pahawh, Ntawv Keeb, Ntawv Caub Fab, Ntawv Soob Lwj) is an indigenous semi-syllabic script, invented in 1959 by Shong Lue Yang, to write two Hmong languages, Hmong Daw (Hmoob Dawb White Miao) and Hmong Njua AKA Hmong Leng (Moob Leeg Green Miao).
Representations
System
Representation (click value to copy)
NΒΊ
92977
UTF-8
F0 96 AC B1
UTF-16
D8 1A DF 31
UTF-32
00 01 6B 31
URL-Quoted
%F0%96%AC%B1
HTML hex reference
𖬱
Wrong windows-1252 Mojibake
Γ’βΕΓ°β±
Encoding: GB18030 (hex bytes)
92 31 E3 31
RFC 5137
\u'16B31'
Bash and Zsh inside echo -e
\U00016B31
C and C++
\U00016B31
C#
\U00016B31
CSS
\016B31
Excel
=UNICHAR(92977)
Go
\U00016B31
JavaScript
\uD81A\uDF31
Modern JavaScript since ES6
\u{16b31}
JSON
\uD81A\uDF31
Java
\uD81A\uDF31
Lua
\u{16B31}
Matlab
char(92977)
Perl
"\x{16B31}"
PHP
\u{16b31}
PostgreSQL
U&'\+016B31'
PowerShell
`u{16B31}
Python
\U00016B31
Ruby
\u{16b31}
Rust
\u{16b31}
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