Profiling of git annex find --not --in web suggests that converting Ref to contain a ByteString, rather than a String, would eliminate a fromRawFilePath that uses about 1% of runtime.

Well, I did the conversion. Running that command does not seem to have sped up by any appreciable amount. But, I did notice several places where using ByteString is certainly more efficient. It may just be that it doesn't matter if git-annex is IO bound etc. Still, glad I did it. done --Joey