What does MDK mean?

[SamCuber]

I have been making a list on every Windows Version available on WorkFlowy and I have been using BetaWiki for research. While researching, I have noticed a bunch of acronyms. For example; PDK, SDK, DR, M, OEM, NEC, RTM, SP, and RC. With more research, I now know what these acronyms mean. Except for "MDK" (3.0 MDK build 59). The closest thing I found was Microcontroller Development Kit. I am unsure if that's true in my case, since it said in the website the complete software development environment for ARM7 , ARM9 , Cortex -M, and Cortex-R4 processor-based devices.so I headed on to BetaArchive to share my question to the public. Also, Some other stuff I found on the Internet is Murder Death Kill, Mobile Development Kit, Mujhse Dosti Karoge and Mekanïk Destrukïw Kommandöh. Please tell me in full detail.

[Zv45Beta]

Perhaps it's Multimedia Development Kit, as this build is a beta version of Win3.0 MME