When a player is looking or clicking at something, they fire a ray that goes until it hits what it needs to hit, or misses.
The result of such a hit is an IRayTraceResult object.

It might be required to import the class to avoid errors.
import crafttweaker.world.IRayTraceResult

All you can do is retrieve information from these objects, here's which:
Be careful though, since all getters that do not return a bool can return null!

nome	type
nome isMiss	type bool
nome isBlock	type bool
nome blockPos	type IBlockPos
nome sideHit	type IFacing

These getters won't actually return anything useful because there isn't a reliable way to raytrace blocks and entities.

nome	type	return value
nome isEntity	type bool	return value always false
nome entity	type IEntity	return value always null