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+2598 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:
Block Elements is a Unicode block containing square block symbols of various fill and shading. Used along with block elements are box-drawing characters, shade characters, and terminal graphic characters. These can be used for filling regions of the screen and portraying drop shadows. Its block name in Unicode 1.0 was Blocks.
Representations
System
Representation (click value to copy)
Nº
9624
UTF-8
E2 96 98
UTF-16
25 98
UTF-32
00 00 25 98
URL-Quoted
%E2%96%98
HTML hex reference
▘
Wrong windows-1252 Mojibake
â–˜
Encoding: GB18030 (hex bytes)
81 37 99 38
RFC 5137
\u'2598'
Bash and Zsh inside echo -e
\u2598
C and C++
\u2598
C#
\u2598
CSS
\002598
Excel
=UNICHAR(9624)
Go
\u2598
JavaScript
\u2598
Modern JavaScript since ES6
\u{2598}
JSON
\u2598
Java
\u2598
Lua
\u{2598}
Matlab
char(9624)
Perl
"\x{2598}"
PHP
\u{2598}
PostgreSQL
U&'\2598'
PowerShell
`u{2598}
Python
\u2598
Ruby
\u{2598}
Rust
\u{2598}
Click the star button next to each label to set this representation as favorite or remove it from the favorites. Favorites will be shown initially. (Favorites are stored locally on your computer and never sent over the internet.)