In the various bundles of good ideas that represent result set
"standards" in the library and greater world, apart from the
atom/opensearch <totalResults> element, is there an expectation of how
one should package a number when that is *all* that is being
requested?

Use Case:
  dear dataset:
       if I asked you for "steamboat" records, how many would you send me?
           signed:  curious

  dear curious:
      12
        signed: dataset

I'm inclined to return just the number as Content-Type: text/plain.

Clearly the semantics of the query string require a mutual
understanding, but that's not my specific concern here.

Walter