Please implement a way to force deactivate the mod on serverjoin when the server sends a certain colourcode combination to the client like with the voxelmap.

this mod is open source. any protections built into this mod would be trivially removable in a fork.

I'm sympathetic to server owners having their maps stolen, but the MC protocol does not hide this data at all. For example, even with a DRM thing built-in, players could capture a ReplayMod recording, then open that recording in WorldTools and download the map there. Basically its impossible to actually prevent.

Similar discussion on alternative WDL tools: mircokroon/minecraft-world-downloader#63