This character is a Other Punctuation and is mainly used in the Syriac script.
The glyph is not a composition. It has no designated width in East Asian texts. In bidirectional text it is written as Arabic letter from right to left. When changing direction it is not mirrored. The word that U+0704 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 colon, :, is a punctuation mark consisting of two equally sized dots aligned vertically. A colon often precedes an explanation, a list, or a quoted sentence. It is also used between hours and minutes in time, between certain elements in medical journal citations, between chapter and verse in Bible citations, and, in the US, for salutations in business letters and other formal letter writing.
Representations
System
Representation (click value to copy)
Nº
1796
UTF-8
DC 84
UTF-16
07 04
UTF-32
00 00 07 04
URL-Quoted
%DC%84
HTML hex reference
܄
Wrong windows-1252 Mojibake
Ü„
Encoding: GB18030 (hex bytes)
81 31 9A 30
RFC 5137
\u'0704'
Bash and Zsh inside echo -e
\u0704
C and C++
\u0704
C#
\u0704
CSS
\000704
Excel
=UNICHAR(1796)
Go
\u0704
JavaScript
\u0704
Modern JavaScript since ES6
\u{704}
JSON
\u0704
Java
\u0704
Lua
\u{704}
Matlab
char(1796)
Perl
"\x{704}"
PHP
\u{704}
PostgreSQL
U&'\0704'
PowerShell
`u{704}
Python
\u0704
Ruby
\u{704}
Rust
\u{704}
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