+dists/stable/contrib/source/
+
+dists/stable/non-free/
+dists/stable/non-free/binary-all/
+dists/stable/non-free/binary-i386/
+dists/stable/non-free/binary-m68k/
+ ...
+dists/stable/non-free/source/
+
+dists/testing
+[everything like in stable]
+
+dists/unstable
+[ditto]