The suffix refers to one of the most famous Chinese gaming forums and cracking groups active during the 2010s. Founded by an individual known as "Bird Sister," 3DM was notorious for bypassing digital rights management systems on major PC releases.
Square Enix had released a free, DRM-free demo for FFXV. 3DM discovered that the executable (.exe) file from this demo could be swapped into the full game’s unencrypted folder, effectively bypassing the security intended for the retail version. Performance vs. Security FINAL FANTASY XV WINDOWS EDITION-3DM