jelos.org/docs/systems/ecwolf.md

ECWolf

.ecwolf files

These files must be created for each Wolfenstein 3D compatible game. The file contains PATH variable that points to the subfolder containing the game's game files, DATA variable with the extension of the game files and PK3 variables for each separate package file to load. PK3 variables must be sequentially numbered with _1, _2 etc.

Example: /roms/ecwolf/wolfenstein3d.ecwolf contains

PATH=Wolfenstein 3D
DATA=WL6
PK3_1=/roms/ecwolf/ecwolf.pk3
-- end --

where the Wolfenstein 3D game files have extension .WL6

Note: the data value must match the file extension of the game exactly and is case sensitive so WL6 is not the same as wl6

Note: don't leave any space between GRP or PATH and = and enclose filenames containing spaces with "quotes"

Note: add -- end -- to the end of the file

Example: /roms/ecwolf/spear of destiny.ecwolf contains

PATH=SOD
DATA=SOD
PK3_1=/roms/ecwolf/SOD/ecwolf.pk3
-- end --

where the Spear of Destiny game files have extension .SOD

Note: add -- end -- to the end of the file