src/game/java/net/minecraft/client/GuiMessage.java

package net.minecraft.client;

import javax.annotation.Nullable;
import net.minecraft.network.chat.Component;
import net.minecraft.network.chat.MessageSignature;
import net.minecraft.util.FormattedCharSequence;
import net.minecraftforge.api.distmarker.Dist;
import net.minecraftforge.api.distmarker.OnlyIn;

@OnlyIn(Dist.CLIENT)
public record GuiMessage(int addedTime, Component content, @Nullable MessageSignature signature, @Nullable GuiMessageTag tag) {
    @Nullable
    public GuiMessageTag.Icon icon() {
        return this.tag != null ? this.tag.icon() : null;
    }

    @OnlyIn(Dist.CLIENT)
    public static record Line(int addedTime, FormattedCharSequence content, @Nullable GuiMessageTag tag, boolean endOfEntry) {
    }
}