WordPress at a glance
function is not described

get_background_color() WP 3.0.0

Retrieve value for custom background color.

No Hooks.

Return

String.

Usage

get_background_color();

Code of get background color: wp-includes/theme.php WP 5.2.2

<?php
function get_background_color() {
	return get_theme_mod( 'background_color', get_theme_support( 'custom-background', 'default-color' ) );
}