I researched this a while, but I do not think Brad Geng committed any code to Mupen64 or Mupen64Plus (unless he used an alias, which is a possibility of course). That said, Mupen64Plus is licensed by the GPL, so as long as I am adhering to the terms of that license, neither he nor anyone else on the Mupen64Plus team have grounds for a DMCA complaint, even if I weren't planning to share patches back upstream after the app is out of Beta (I am, but just saying).
From what I understand, the reason GPL apps can't be released in
Apple's App Store, is because of the following section of the GPL:
Each time you redistribute the Program (or any work based on the Program), the recipient automatically receives a license from the original licensor to copy, distribute or modify the Program subject to these terms and conditions. You may not impose any further restrictions on the recipients’ exercise of the rights granted herein.
The Apple App Store imposes copy restrictions and others, which violate this agreement. These restrictions are not in the Android developers agreement, as far as I can see (I read it carefully a number of times to find anything that might conflict between the licenses, but I couldn't find any). The agreement gives Google some more rights to use and retain pieces for advertisement and testing purposes, but extra rights are not the same thing as restrictions, so that doesn't violate the GPL either.
I don't mean to bash Yongzh at all here, but just to clarify about N64oid, Yongzh actually IS a perfectly valid candidate for DMCA complaints, because he is in violation of the following section of the GPL by not releasing the full source code for N64oid:
If identifiable sections of that work are not derived from the Program, and can be reasonably considered independent and separate works in themselves, then this License, and its terms, do not apply to those sections when you distribute them as separate works. But when you distribute the same sections as part of a whole which is a work based on the Program, the distribution of the whole must be on the terms of this License, whose permissions for other licensees extend to the entire whole, and thus to each and every part regardless of who wrote it.
Yongzh could actually easily get around this problem by releasing his closed-source plug-ins separately from the core app rather than distributing them as parts of a whole. If he were to do that, then there would be no grounds for DMCA complaints against him either.
Anyway, it seems the most obvious reason for Brad's DMCA complaint against my app is less to do with any alleged GPL violation, and more to do with wanting to remove competition and increase ad revenues.