Chart Files are files that are the outcome of the finished "chart" created on Feedback, similar to Midi files, but Chart files are text.
You can download Chart files at Scorehero.com.
You will need Leff's (From Scorehero) Chart2Mid2Chart Converter. Download Here.
Simply import the Chart File, click convert, and Find the Midi file in the same spot.
The same application is available as a java application, it works well on linux but I'm not sure about mac, it should work there without any problems at all.
In any case here's the link.