The Tor Browser / file revision

 // The last Environment on the environment chain always has .type == "object" and .object === the global object.

 var g = newGlobal();

 var dbg = new Debugger;

 var gw = dbg.addDebuggee(g);

 g.eval("function h() { debugger; }");

 var hits = 0;

 dbg.onDebuggerStatement = function (hframe) {

     var env = hframe.older.environment;

     while (env.parent)

         env = env.parent;

     assertEq(env.type, "object");

     assertEq(env.object, gw);

     hits++;

 };

 g.eval("h();");

 g.eval("(function () { h(); return []; })();");

 g.eval("with (Math) { h(-2 * PI); }");

 assertEq(hits, 3);