This 2005 post from the NSA’s internal newsletter SIDToday describes how the relationship between the agency and its Czech counterpart USZI developed into a “third party relationship”: see the Intercept article NSA Used Porn to “Break Down Detainees” in Iraq — and Other Revelations From 297 Snowden Documents, 1 March 2018.
This NSA presentation from 24 June 2009 explains how to use the email search functionality within XKeyScore: see the Intercept article XKEYSCORE: NSA’s Google for the World’s Private Communications, 1 July 2015.
This undated NSA presentation sets out the network-mapping tool Treasure Map, and supplies information on some of the agency’s collection access points: see the Intercept article New Zealand Launched Mass Surveillance Project While Publicly Denying It, 15 September 2014.
This 21 May 2009 presentation from the NSA’s Center for Content Extraction includes a slide that shows that the communications of 122 heads of government were stored in the agency’s central “Target Knowledge Base”, 11 of whom are named. The collection for most of these targets was automated: see the Der Spiegel article ‘A’ for Angela: GCHQ and NSA Targeted Private German Companies and Merkel, 29 March 2013.