yiisoft/yii — pull request #2152 by acorncom (2013-02-27 00:14:57+00:00)
Title: Added in Fileinfo PECL extension check for CFileValidator

The mimetype checking is a really slick feature, but it's buried in Yii. Adding it to the requirements page might both allow a quick check to see if things are setup (for those of us using it) and might draw additional attention to this nifty feature.