Similar to FITS

4C$ - 4Cast/2 Datafile
4GE - Informix 4G Compiled source code file
4GL - Informix 4GL language source code file
4MD - Musical file
4SW - 4DOS Swap file
4TH - Forth language source code file ForthCMP - LMI Forth
668 - Music the mixing is always at 12048Hz

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