wp_get_sidebar()

wp_get_sidebar( string $id ): array|null

function wp_get_sidebar( $id ) {
	global $wp_registered_sidebars;

	foreach ( (array) $wp_registered_sidebars as $sidebar ) {
		if ( $sidebar['id'] === $id ) {
			return $sidebar;
		}
	}

	if ( 'wp_inactive_widgets' === $id ) {
		return array(
			'id'   => 'wp_inactive_widgets',
			'name' => __( 'Inactive widgets' ),
		);
	}

	return null;
}