The usual assumption is that {vabDot} is an adverbial meaning "even", in the sense of emphasizing that something unexpected is indeed the case. But we have no idea for sure, since Okrand's never given us a gloss of the word. We don't even know 100% what part of speech it is. (Another word in that sentence, {Qej}, also has an unknown precise meaning, though at least we know it's a verb because of the -bogh.)