suddenly it struck me that here was a person, not all that different from myself.

부사구 앞으로 나와서 s,v 도치되고,
a person 하고 not all that different from myselft이문장이 동격인건 알겠는데요.

not all that different from myselft이 문법적으로 어떻게 구성된건가요?