It doesn't play midi files
...midi files.
The DGX-220 can play MIDI files, and there is a USB MIDI driver for these models, but there are no applications for XML files for these keyboards.
If you mean midi player, it is able to play midi files. Mostly such programs are free of charge and support only this specific function.
You can't do that :D
export to midi first
Midi to USB cables run from some sort of musical device (electronic keyboard, electric guitar, etc) to a USB port on your computer. You can use it to transfer midi files (music files) into your computer.
Next to none.
Many MIDI files on the internet are free and legal to download. Theoretically, a MIDI version of a popular song could be called a "derivative work" and be considered a form of copyright infringement, but I doubt that anyone cares that much about MIDI files anymore.
1983
Use google and search for midi files or instrumental mp3's.
it is a standard song file