WordPress at a glance
function is not described

WP_Customize_Setting::is_current_blog_previewed() public WP 4.2.0

Return true if the current site is not the same as the previewed site.

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

No Hooks.

Return

true|false. If preview() has been called.

Usage

$WP_Customize_Setting = new WP_Customize_Setting();
$WP_Customize_Setting->is_current_blog_previewed();

Changelog

Since 4.2.0 Introduced.

Code of WP_Customize_Setting::is_current_blog_previewed() WP 5.7.2

<?php
public function is_current_blog_previewed() {
	if ( ! isset( $this->_previewed_blog_id ) ) {
		return false;
	}
	return ( get_current_blog_id() === $this->_previewed_blog_id );
}