pour résumer:
1 Copy the game folder to a different location.
2 Create a file (or just copy a file and rename it) named matchingDevMode (no extension).
3 Launch the game from the copied folder.
4 In the laucher's options, in the bottom-left corner, under server, select "dev".
5 Confirm the prompt.
6 Wait for the game to update.
7 Launch the game.
8 You are now in the DEV test.