TrinityCore/TrinityCore — comment on commit dc81555740a7e339755ce0b690b98d058f5be726
File:  line 0
By MachiavelliTrinity:

That's because in chat packtets there's a segment with a "chat tag" flag, ie. 0x1 for AFK, 0x2 for DND, 0x4 for GM, etc. (Not sure if the numbers are right, but it was an example...)