Eeh, worst case scenario you'll get sued as Microsoft will have no problem with handing over everything they have from your Windows installation information, GitHub accounts, NPM authentication and everything else they own today if the courts tell them to.
You can't just commit crimes on the open internet without really hiding IPs and what not, and expect that to not come back to haunt you eventually. Kind of poor form to suggest otherwise too.
Who said it is a crime, are you a lawyer?
I'm not saying yay/nay if this is a crime or not, but if you think it might be, and you create a new account on GitHub to "be anonymous", you're not taking opsec seriously enough for something you believe might be a crime.
By the way, generally judges or juries would be the ones to decide if something was illegal or not, it's not the lawyers who decide this, in any country I'm familiar with.
But we like to pretend that the justice system delivers justice evenhandedly I suppose.
You could also create a text document instead of a software that details the mechanism used to fool other MIDI decoders and publish only that (for now).
Finally, familiarize yourself with the Art. 6 Software Directive (2009/24/EC) / §69e UrhG — decompilation for interoperability. It may be your ticket for a legal status in Germany/EU.
Does it matter? What's important is if it can happen or not, and how if so. We already know that MPAA is willing to basically do whatever, even contribute themselves to piracy, if it means they can put people in jail for copying stuff eventually. They themselves also gotten in trouble for copyright violations themselves in the past, so doesn't seem like they're hiding away from breaking a little bit of laws to hunt pirates.