master/unlock__upgrade_8php_source.html

 <?php
 $mutex = _elgg_services()->mutex;

 if ($mutex->isLocked('upgrade')) {
     $mutex->unlock('upgrade');
 }

 return elgg_ok_response('', elgg_echo('upgrade:unlock:success'));
elgg_ok_response
elgg_ok_response($content= '', string|array $message= '', string $forward_url=null, int $status_code=ELGG_HTTP_OK)
Prepares a successful response to be returned by a page or an action handler.
Definition: pagehandler.php:224

$mutex
$mutex
Unlocks the upgrade script.
Definition: unlock_upgrade.php:6

elgg_echo
elgg_echo(string $message_key, array $args=[], string $language= '')
Elgg language module Functions to manage language and translations.
Definition: languages.php:17

_elgg_services
_elgg_services()
Get the global service provider.
Definition: elgglib.php:351