Here, when we apply in a `Settings.php` file:

    $wgCompatablesUseESI=true;

Breaks the test site with message:

    Nov  8 19:56:42 10.5.7.43 apache2[17020]: [error] [client 199.27.78.20] PHP Fatal error:  Cannot access static:: when no class scope is active in /srv/webplatform/wiki/test/extensions/CompaTablesNew/Compatables.class.php on line 96, referer: http://docs.webplatform.org/test/Main_Page