Idea

If the client receives one of the following

  "multiplayer.disconnect.expired_public_key": "Expired profile public key. Check that your system time is synchronized, and try restarting your game.",
  "multiplayer.disconnect.invalid_public_key_signature": "Invalid signature for profile public key.\nTry restarting your game.",
  "multiplayer.disconnect.unsigned_chat": "Received chat packet with missing or invalid signature.",

kick messages or one of the following

  "chat.disabled.expiredProfileKey": "Chat disabled due to expired profile public key. Please try reconnecting.",
  "chat.disabled.chain_broken": "Chat disabled due to broken chain. Please try reconnecting.",

chat messages, NCR could:

• intercept the message
• rewrite the message to be more understandable
• in kick screen, offer an option to rejoin with enabled signatures where relevant
• where possible, attempt to fix the issue by itself (e.g. expired key)

Reasoning

Vanilla messages seem to be intentionally cryptic and the user may not draw the connection that things like that may be caused by NCR. So if NCR rewrote the message and maybe offered some help, the user would, if not fix, then at least report the issue to NCR instead of Mojang's bug tracker.

Other Information

1.19.3+

The problem is that this disconnect message can be sent for a variety of reasons, of which the bug in question is only one. I will not implement any workarounds for it unless 1.19.3 will be released without a fix for it.

As #272 is fixed upstream anyway and can soon be closed, I've broadened this issue to be a bit more generic.