-// 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
+//
+// The following URLs are read-only, but otherwise interchangeable
+// with the above:
+//
+// http://1f4b0bc7583c2a7f9102c395f4ffc5e3-45--foo.example.com/foo/bar.txt
+// http://1f4b0bc7583c2a7f9102c395f4ffc5e3-45--.invalid/foo/bar.txt
+// http://collections.example.com/by_id/1f4b0bc7583c2a7f9102c395f4ffc5e3%2B45/foo/bar.txt
+// http://collections.example.com/by_id/zzzzz-4zz18-znfnqtbbv4spc3w/foo/bar.txt
+//
+// If the collection is named "MyCollection" and located in a project
+// called "MyProject" which is in the home project of a user with
+// username is "bob", the following read-only URL is also available
+// when authenticating as bob:
+//
+// http://collections.example.com/users/bob/MyProject/MyCollection/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
+//
+// Collections can also be accessed (read-only) via "/by_id/X" where X
+// is a UUID or portable data hash.