Location of core.internal.traits : CoreUnqual in Dlang GitHub repo

[data pulverizer via Digitalmars-d-learn]

Hi all,

I've been looking for where `CoreUnqual` is defined in the Dlang 
repos. I've tried searching in dmd and phobos but only found the 
reference usage in std.traits:

import core.internal.traits : CoreUnqual;

I'd like to know where it is defined so I can (attempt to!) study 
the code.

Thanks in advance.