It's just a better looking version of f3 :p
^^^This mod is allowed. This mod is only useful for allowing you to see:
- A way more precise FPS-Counter that is updating every 1/50th second
- Your coordinates with a selectable precision
- Your Direction
- Your active potion effects
- Your armor status
- Your biome
- Your ping to a server
- How many players are connected to the server you are playing on
- Your current time
- Entity count
It doesn't create an unfair advantage due to other players can get it, so its allowed.