WP_Site_Icon::delete_attachment_data( int $post_id )

Source

File: wp-admin/includes/class-wp-site-icon.php

public function delete_attachment_data( $post_id ) {
		$site_icon_id = get_option( 'site_icon' );

		if ( $site_icon_id && $post_id == $site_icon_id ) {
			delete_option( 'site_icon' );
		}
	}