WordPress at a glance
function is not described

WP_Theme::get_allowed() public WP 3.4.0

Returns array of stylesheet names of themes allowed on the site or network.

{} It's a method of the class: WP_Theme{}

Hooks from the method
Return

String[]. Array of stylesheet names.

Usage

$result = WP_Theme::get_allowed( $blog_id );
$blog_id(int)
ID of the site.
Default: current site

Changelog

Since 3.4.0 Introduced.

Code of WP_Theme::get_allowed() WP 5.5.1

<?php
public static function get_allowed( $blog_id = null ) {
	/**
	 * Filters the array of themes allowed on the network.
	 *
	 * Site is provided as context so that a list of network allowed themes can
	 * be filtered further.
	 *
	 * @since 4.5.0
	 *
	 * @param string[] $allowed_themes An array of theme stylesheet names.
	 * @param int      $blog_id        ID of the site.
	 */
	$network = (array) apply_filters( 'network_allowed_themes', self::get_allowed_on_network(), $blog_id );
	return $network + self::get_allowed_on_site( $blog_id );
}