Video game engines with Dlang.

[Shuba]

I've been searching the internet looking for game engines that I 
can use Dlang to program, but they are always the same ones; say 
Dagon, Raylib, Derelict and even BindBC. But I wanted to ask you 
if you could mention any other game engine that uses D for 
programming that I might not know, it would help me a lot (I 
guess).

Incidentally, could someone explain to me what exactly this does:

     "public final pure nothrow @property @safe @safe @nogc ref 
File file file() {
             return _file;
     }"

It's code from a dub package (specifically one called 
"terminal"), but I don't understand why all that.