I'm certain the NDA for Xcode 3 and Leopard has expired. I hope it's not necessary to cite a paragraph in the NDA for this.
As to the Xcode 6 NDA, my first thought is, "Look in the Legal Agreements for your developer account." One should be able to find the text of those Agreements by signing into one's developer account, going to "Your Account", and looking under the "Legal Agreements" topic on the left.
I would start with the most recent agreements. Look at any section whose heading contains the words "confidential" and/or "pre-release".
I can neither confirm nor deny the existence of an entire numbered section titled "Confidentiality". There may or may not be a PDF, that may or may not download, when possibly clicking on whatever might show up under "Legal Agreements". YMMV.