WordPress at a glance
function is not described

get_theme_support() WP 3.1.0

Gets the theme support arguments passed when registering that support

  • Global. Array. $_wp_theme_features

No Hooks.

Return

Mixed. The array of extra arguments or the value for the registered feature.

Usage

get_theme_support( $feature );
$feature(string) (required)
the feature to check

Code of get theme support: wp-includes/theme.php VER 5.1.1

<?php
function get_theme_support( $feature ) {
	global $_wp_theme_features;
	if ( ! isset( $_wp_theme_features[ $feature ] ) ) {
		return false;
	}

	if ( func_num_args() <= 1 ) {
		return $_wp_theme_features[ $feature ];
	}

	$args = array_slice( func_get_args(), 1 );
	switch ( $feature ) {
		case 'custom-logo':
		case 'custom-header':
		case 'custom-background':
			if ( isset( $_wp_theme_features[ $feature ][0][ $args[0] ] ) ) {
				return $_wp_theme_features[ $feature ][0][ $args[0] ];
			}
			return false;

		default:
			return $_wp_theme_features[ $feature ];
	}
}