Mine Fortress is marked as a client-side mod

Mine Fortress is marked as a client-side mod but it's a mod on both sides: client and server .

here is the link : https://www.curseforge.com/min…-1671308848-0-gaNycGzNDf0

thank you

can you add Fortress gamemode in the options, please?
It is mandatory to join the server because if not there is a problem with the client's data.

it is a specific mod: Mine Fortress. It adds (and it's the only mod in my opinion) a gamemode named fotress.
if it is not possible to add gamemode in the options, I may find another way to add the mode to a server.