[XHR2] term "flag", for authors

I'm an author, not an implementor, so my question is from an author's point
of view.

There's used the term "flag" in the specification, it's once used,
apparently, to represent the XMLHttpRequest Constructor Function's
argument<http://dev.w3.org/2006/webapi/XMLHttpRequest-2/#dom-xmlhttprequest-anon>,
to set the boolean "anon".

Then it is used in the OPENED state to set a boolean "send()
flag<http://dev.w3.org/2006/webapi/XMLHttpRequest-2/#send-flag>"
and then in the DONE state to to set a boolean "error
flag<http://dev.w3.org/2006/webapi/XMLHttpRequest-2/#error-flag>
".

But there's no such boolean variables in the XHR object, they aren't
mentioned in the
IDL<http://dev.w3.org/2006/webapi/XMLHttpRequest-2/#xmlhttprequest>and
as an author I don't have acces to those "flags".

The term "flag" isn't defined in the spec, nor in the DOM, nor in the
Mozilla's JavaScript Reference (I haven't read the ECMAScript reference). I
don't know where it's defined or if it's something "obvious" that I should
know.

I can see that those "flags" are used in the algorithms so I suspect that
they could be just object's implementation's internal variables supposed to
be used only internally, and that my way to know (e.g.) errors, is just
watching the thrown exceptions, but I'm not sure, and this is not explicitly
specified.

It's also said, that the XMLHttpRequest has some "metadata variables" and
one of those is a "list of author request
headers<http://dev.w3.org/2006/webapi/XMLHttpRequest-2/#author-request-headers>",
that doesn't have an API to be accessed (or at least I can't find it), I
might suppose that it's another internal variable, intent to be an
implementor's resource to achieve the specified algorithms.

I want to know if I am understanding or misinterpreting the spec and what,
by the spec, is what I'm supposed to be able to use.

I hope I made myself understood, I apologize me for my bad English and my
newbieness.

Thanks,

Sebastian Ramirez