Source

File: wp-includes/option.php

function delete_user_setting( $names ) {
	if ( headers_sent() ) {
		return false;
	}

	$all_user_settings = get_all_user_settings();
	$names             = (array) $names;
	$deleted           = false;

	foreach ( $names as $name ) {
		if ( isset( $all_user_settings[ $name ] ) ) {
			unset( $all_user_settings[ $name ] );
			$deleted = true;
		}
	}

	if ( $deleted ) {
		return wp_set_all_user_settings( $all_user_settings );
	}

	return false;
}