mixin template

[Dan Killebrew]

What is the difference between:
A
-----------
template Foo() {
  int x = 5;
}
B
-------------
mixin template Foo() {
  int x = 5;
}

The full example is from the first code sample on 
http://dlang.org/template-mixin.html  Both A and B compile and 
when run, have the exact same output. So how is 'mixin template' 
different from 'template'?

Full example, slightly modified to actually run:
import std.stdio;

 template Foo() {
//mixin template Foo() {
  int x = 5;
}

mixin Foo;

struct Bar {
  mixin Foo;
}

void main() {
  writefln("x = %d", x);  // prints 5
  {
    Bar b;
    int x = 3;

    writefln("b.x = %d", b.x); // prints 5
    writefln("x = %d", x);     // prints 3
    {
      mixin Foo;
      writefln("x = %d", x);   // prints 5
      x = 4;
      writefln("x = %d", x);   // prints 4
    }
    writefln("x = %d", x);     // prints 3
  }
  writefln("x = %d", x);       // prints 5
}