Mozilla Developer Network の略でMDNだったけどもはやMDNは"MDN"だよみたいなこと言ってる?
“Mozilla Developer Network” simply isn’t accurate. Furthermore, pretty much no one refers to MDN as “Mozilla Developer Network.” It’s always “MDN.” However, there is a lot of love for the name “MDN” and we don’t want to get rid of all of that, which is why we’re giving it the IBM / KFC treatment and keeping the iconic abbreviation and commonly used name, while no longer using the words that the acronym used to stand for. We’re not getting rid of MDN, we’re being clear about what it is – it’s MDN Web Docs.
The Future of MDN: A Focus on Web Docs - Mozilla Open Design https://blog.mozilla.org/opendesign/future-mdn-focus-web-docs/