Actually I suppose technically the `//` is part of the 'scheme-specific' identifying string for HTTP, so you could argue that 'flags' doesn't have any leading slashes in its identifiers.  But that doesn't feel especially helpful.  Feel free to get some other opinions on it from Matt and Luke, and if they're happy with it, I don't mind keeping the discrepancy, but otherwise, go with a consistent delimiter.

And remember we don't need a multiple-file syntax outside of imageset.