Labymod does not handle the Delete Messages packet
If the server sends the Delete Messages packet (https://wiki.vg/Protocol#Delete_Message) to a vanilla client, it replaces the message in the chat, which has an identical signature to the packet, with the note "This chat message has been deleted by the server" in the client's chat.
However, when the packet is sent to players with Labymod, nothing happens. The message remains visible in the chat. I assume that Labymod does not process this packet.
Operating System: Windows 10
LabyMod Version: 4.0.10
Minecraft Version: 1.20.1