Adding prefixes to player's Nametag

I've seen several servers adding prefixes to player's nametags without their skin changing. Here is a picture of what I'm talking about. How do they do this? Do they use scoreboards? They don't use any type of NameTagAPI or anything like that. However they do have a custom plugin named PacketTagApi and PacketTagGroup as well as PacketWrapper. I don't know if this has anything to do with it. I would like to also make my own API. How would I add prefixes to nametags like shown in the image below?

 

@plisov
You can do this by "removing" the player entity and re-adding the player with the same UUID, but a different name.

Use this to remove the player:
http://wiki.vg/Protocol#Destroy_Entities

And use this to spawn in the new custom player.
http://wiki.vg/Protocol#Spawn_Player

 

Set name and set display name.

 

@TheEnderman
If you mean using the setDisplayName method, then no, that won't work. From the java docs (All hail the Java Docs)

 

Seems to work for me...

 

How do I use this?