_is_utf8_charset() │ WP 6.6.1

Indicates if a given slug for a character set represents the UTF-8 text encoding.

A charset is considered to represent UTF-8 if it is a case-insensitive match of "UTF-8" with or without the hyphen.

Example:

true  === _is_utf8_charset( 'UTF-8' );
true  === _is_utf8_charset( 'utf8' );
false === _is_utf8_charset( 'latin1' );
false === _is_utf8_charset( 'UTF 8' );
// Only strings match.
false === _is_utf8_charset( [ 'charset' => 'utf-8' ] );

is_utf8_charset should be used outside of this file.

Internal function — this function is designed to be used by the kernel itself. It is not recommended to use this function in your code.

No Hooks.

Return

true|false. Whether the slug represents the UTF-8 encoding.

Usage

_is_utf8_charset( $charset_slug );
$charset_slug(string) (required)
Slug representing a text character encoding, or "charset". E.g. "UTF-8", "Windows-1252", "ISO-8859-1", "SJIS".

Changelog

Since 6.6.1 Introduced.

_is_utf8_charset() code WP 6.8

wp-includes/compat.php 
function _is_utf8_charset( $charset_slug ) {
	if ( ! is_string( $charset_slug ) ) {
		return false;
	}

	return (
		0 === strcasecmp( 'UTF-8', $charset_slug ) ||
		0 === strcasecmp( 'UTF8', $charset_slug )
	);
}