This character is a Other Symbol and is commonly used, that is, in no specific script.
The glyph is not a composition. It has no designated width in East Asian texts. In bidirectional text it acts as Other Neutral. When changing direction it is not mirrored. The word that U+2303 forms with similar adjacent characters prevents a line break inside it.
The Wikipedia has the following information about this codepoint:
In computing, a Control keyCtrl is a modifier key which, when pressed in conjunction with another key, performs a special operation (for example, Ctrl+C). Similarly to the Shift key, the Control key rarely performs any function when pressed by itself. The Control key is located on or near the bottom left side of most keyboards (in accordance with the international standard ISO/IEC 9995-2), with many featuring an additional one at the bottom right.
On keyboards that use English abbreviations for key labeling, it is usually labeled Ctrl (Control or Ctl are sometimes used, but it is uncommon). Abbreviations in the language of the keyboard layout also are in use, e.g., the German keyboard layout uses Strg as required by the German standard DIN 2137:2012-06. There is a standardized keyboard symbol (to be used when Latin lettering is not preferred). This symbol is encoded in Unicode as U+2388 helm symbol⎈, but it is very rarely used.
Representations
System
Representation (click value to copy)
Nº
8963
UTF-8
E2 8C 83
UTF-16
23 03
UTF-32
00 00 23 03
URL-Quoted
%E2%8C%83
HTML hex reference
⌃
Wrong windows-1252 Mojibake
⌃
Encoding: GB18030 (hex bytes)
81 36 E7 38
Adobe Glyph List
control
RFC 5137
\u'2303'
Bash and Zsh inside echo -e
\u2303
C and C++
\u2303
C#
\u2303
CSS
\002303
Excel
=UNICHAR(8963)
Go
\u2303
JavaScript
\u2303
Modern JavaScript since ES6
\u{2303}
JSON
\u2303
Java
\u2303
Lua
\u{2303}
Matlab
char(8963)
Perl
"\x{2303}"
PHP
\u{2303}
PostgreSQL
U&'\2303'
PowerShell
`u{2303}
Python
\u2303
Ruby
\u{2303}
Rust
\u{2303}
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