Hi,
So does this mean that NSA let BND access its intercept backend?
I think no. But they provide soft- and hardware like XKS or Wealthycluster systems and selectors via NSA's European Technology Center (ETC) in Wiesbaden and the SUSLAG (NSA Special US Liaison Activity Germany) in the Mangfall barrack (Bad Aibling).
Or did this data come from a BND-intercept backend?
From own or cooperation "intercept backends" between NSA's FPA/SSO (+UKUSA 5Eyes, CIA) and BND-TA. In the Snowden docs are two projects: "Monkeyshoulder" (in Germany with NSA and GCHQ) and "Wharpdrive" (i think foreign countries, 2013 exposed and than terminated). Than there was "Eikonal" aka "Granat"/"Karat" (in Germany), "Glotaic" aka "Globe" (with CIA in Germany) and now we know about "Smaragd" (outside the EU) aside from nine additional blacked-out projects as seen in https://netzpolitik.org/2015/angezapfte-glasfasern-bnd-und-kanzleramt-versch....
-- Katana