Mod Observer
IMPORTANT: This project has experimental status
As the name suggests, ModObserver monitors which mods are loaded in the player's client. When connecting to a server, it transmits information about all installed mods to the server. The game server administrator can configure allowed and prohibited modifications on their platform.
When you try to join a server that requires ModObserver, you will receive a message similar to the following:

For server owners: To enable full functionality of the system, you need to install the corresponding plugin.