a couple thoughts, I would agree with the general lack of a rigid belief system, but to me personally it mainly refers to a rejection of things like, "the collective", "the masses", "the someday revolution" or even just describing anarchy, as someone else mentioned, a "grand scheme" or a plan with a definite goal (non hierarchical lack of oppression, or stateless moneyless classless society) in mind and a way to get there, that includes all anarchists, when it would be more accurate and, well, real, to try to explain what individuals or groups are doing, and what their real, tangible, and realistically attainable goals are.
someone else mentioned the concept of emptiness, and this is another important aspect to how I think personally. I said something about gaining an "optimistic nihilism" in another post but that's problematic because nihilism is clearly realistic, but what I was trying to say by optimism, is that the emptiness to me, ironically yields an optimistic feeling because I don't feel weighed down by gods, predestination, inherent universal "meaning of life", etc. because nothing matters and all the stars in the universe go dark eventually, I am my own god, I make my own destiny and meaning, I set my own standards and I alone enforce them.