In this version Meynaf added custom code and graphics.dat to remove some engine limitations.
It’s actually a mix of several versions of the game, from Atari ST v1.2 to Amiga v3.6, and dungeons made by him.
See here
It has its own discussion thread on EAB
Custom dungeons for Dungeon Master
Dungeons made by others (including original FTL dungeons)
To extract the archive you need LZX tool. See readmes in the archive for more infos.