WordPress at a glance
function is not described

dismiss_core_update() WP 1.0

No Hooks.

Return

true/false.

Usage

dismiss_core_update( $update );
$update(object) (required)

Code of dismiss core update: wp-admin/includes/update.php VER 5.1.1

<?php
function dismiss_core_update( $update ) {
	$dismissed = get_site_option( 'dismissed_update_core' );
	$dismissed[ $update->current . '|' . $update->locale ] = true;
	return update_site_option( 'dismissed_update_core', $dismissed );
}