Andreas Pehnack
Thanks to Ben there is a bunch of grammars for various MIDI Sysex file formats.
Ben made the grammars available on three Github repositories: Sysex Grammar, OSCsar MIDI Sysex Grammar, and Akai AX73 and VX90 MIDI Sysex Grammar.
The first one is a generic grammar for vendor-specific (Sysex) MIDI files and focuses on Non Real Time Universal System Exclusive Messages. There are two grammars covering files for the OSCar synthesizers which were built from 1983 to 1985. The last grammar decodes files being used by Akai AX73 and VX90 voice analog synthesizers dating back to 1986.