wp_ajax_health-check-site-status

See hook in action

See this hook used in plugins:

Select Pluginhealth-check.1.2.3health-check.1.2.6health-check.1.3.2health-check.1.4.0health-check.1.4.2health-check.1.4.3health-check.1.4.4health-check.1.4.5