-// http://zzzzz-4zz18-znfnqtbbv4spc3w.dl.example.com/foo
-// http://zzzzz-4zz18-znfnqtbbv4spc3w.dl.example.com/t=/foo
-// http://zzzzz-4zz18-znfnqtbbv4spc3w--dl.example.com/t=/foo
-// http://1f4b0bc7583c2a7f9102c395f4ffc5e3-45--foo.example.com/foo
-// http://1f4b0bc7583c2a7f9102c395f4ffc5e3-45--.invalid/foo
+// http://zzzzz-4zz18-znfnqtbbv4spc3w.collections.example.com/foo/bar.txt
+// http://zzzzz-4zz18-znfnqtbbv4spc3w.collections.example.com/_/foo/bar.txt
+// http://zzzzz-4zz18-znfnqtbbv4spc3w--collections.example.com/_/foo/bar.txt
+// http://1f4b0bc7583c2a7f9102c395f4ffc5e3-45--foo.example.com/foo/bar.txt
+// http://1f4b0bc7583c2a7f9102c395f4ffc5e3-45--.invalid/foo/bar.txt
+//
+// An additional form is supported specifically to make it more
+// convenient to maintain support for existing Workbench download
+// links:
+//
+// http://collections.example.com/collections/download/uuid_or_pdh/TOKEN/foo/bar.txt
+//
+// A regular Workbench "download" link is also accepted, but
+// credentials passed via cookie, header, etc. are ignored. Only
+// public data can be served this way:
+//
+// http://collections.example.com/collections/uuid_or_pdh/foo/bar.txt