The link to the opcache validate_timestamps setting is incorrect, it does not link to documentation about the setting.

Steps:

1. Make sure your php.ini has opcache.validate_timestamps set to "1" to cause the setup issue (probably have to restart phabricator for this)
2. In phabricator, navigate to: Config -> Setup Issues -> OPcache Config
3. Should have a "In production, OPcache should be configured to never revalidate code. " warning about the validate timestamps setting.

The "PHP Documentation" link references this page:
http://php.net/manual/en/ini.list.php

It should reference this page:
http://php.net/manual/en/opcache.configuration.php

Version

phabricator 8dbc3f184092578026563b4a2fe9f7356dd15dee (Sat, Oct 1) 
arcanist e7906e47cba2006fa46553d462abf1f685845f20 (Fri, Sep 23) 
phutil 027846d5577a195e7a3029872b77b2aba131da54 (Sat, Oct 1)