Comment 9 for bug 173096

James: here's an alternative that seems to do the trick for serving static files in my local tests:

<Files buildlog_*.txt.gz>
  AddEncoding x-gzip gz
</Files>

This applies the AddEncoding directive only to files matching the given filename pattern. It didn't affect any .tar.gz files in my tests. Could you check to see if it works for responses proxied from the librarian?