Thread:Project:Support desk/Spezial:Dateien (Special:Data?) is blank when $wgTmpDirectory is defined in LocalSettings.php/reply (2)

Please delete any cookie information from the debug log when posting it publicly, otherwise anyone could automatically log in into your account (although that won't expose your passwords). I've logged you out so nobody else can login on your account with those cookies.

The debug log doesn't show any error, but it's missing a line saying that the request ended successfully, so maybe a fatal error was produced that it wasn't even logged because the execution was halted before that point. You should check your Apache error logs to see if any error is logged there.