Minecraft if you press F3 + B...

if you press F3 + B this happens:

 

Woah, It's like the red/white their hitboxes and the blue is where they've been.

 

It is a useful thing to do. When doing so it will highlight pretty much all entities. In this case, if you threw an item on the ground, the hitboxes would show up. The red boxes show the hitbox. The blue lines show the direction where the entity is facing. Quite useful in PvP. I never use it though, I keep forgetting. It works on players too.

 

The blue line is their line of sight.
The red box is their top and the white is their hitbox.

It's quite a useful feature

 

This actually helped me in an oitc fight. A person was aiming their bow around the corner, while crouched so I could not see them, but I could see their blue line of sight going around the corner, so I was able to know a person was there.

 

I call hax
I'm trying this when I get to SG with my friends.

 

I DON'T HACK!!! try it yourself in vanilla minecraft!!

 

I already knew some of this stuff.
F3 + H shows all of the item's ID numbers
F3 + B shows hitboxes and line of sight
F3 + A refreshes chunks
That's all I know off the top of my head

 

It's a joke. xD

 

Thanks for showing me, this is pretty cool.

 

Yw! glad I could help! :)

Oh...Lol xD

 

F3 + H also shows an item's durability. You're welcome c:

 

useful for pvp

 

Woah that's cool.

 

Does that coal ore face a direction.... dafuq

 

Thank for showing me!