It should actually be file.chart, but some people accidentally have it saved as file.chart.txt, for some reason. Basically, get rid of the .txt part of the ending and it'll work just fine.
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Goals:
GH1, 2, 80s, 3, Aero: Guitar God (Expert)
My Customs! - Latest: A Taste Of Collapse - Disarmonia Mundi
Music is like candy, you throw out the (w)rappers.
People who rap aren't rappers, they're rap-ists, y'know, like art-ists. Which looks suspiciously like the word "rapist".