Different options related to servers trying to get data about installed mods, fingerprinting your Minecraft installation etc.

Hide mod from ModVersions packet

Forge only.
Forge mod loader has few additional packets client and server can exchange during handshake process.
Server and client may inform each other about list of installed mods on both sides.

Translation/Keybind Exploit

Disconnect on Attempt

You will be immediately disconnected when mod detects server is trying to use translation exploit.
Translation exploit uses very quick sign open packets sent by server during login process, and requesting your client to "translate" key that may be present only if specific mod is loaded. Also works with anvils.
https://wurst.wiki/sign_translation_vulnerability

Log Attempts

Save all exploit attempts to log. Open Scripting ⇒ Debug module to see logs.

Resource Packs

Disconnect on malicious behavior

You will be immediately disconnected if server sends invalid URL, or if host from that URL can be resolved to local IP (loopback, LAN or link-local).

Always show confirmation on resource pack request from the server

By default if you accept resource pack once, server may send any amount of additional resource packs and they all will get downloaded automatically.

Display resource pack URLs

Resource pack URLs will be displayed on the confirmation screen. You can see by yourself if server is doing something shady.

Log resource packs details

Save all resource pack requests to log. Open Scripting ⇒ Debug module to see logs.