wp-includes/class-wp-customize-setting.php:291Return true if the current site is not the same as the previewed site.
bool public function is_current_blog_previewed() { if ( ! isset( $this->_previewed_blog_id ) ) { return false; } return ( get_current_blog_id() === $this->_previewed_blog_id ); }Introduced in 4.2.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/class-wp-customize-setting.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.