In addition to extension=fileinfo.soI also had to add mime_magic.magicfile=/usr/share/file/magicto my php configuration. Then, I instantiate Finfo thus:<?php$mimeMagicFile = get_cfg_var('mime_magic.magicfile');$finfo = new finfo(FILEINFO_MIME, $mimeMagicFile);?>(This is despite the rumours I hear about the default being exactly what I set it to anyway.)