start = element prestodelta { newpackage+ }
newpackage = element newpackage {
  attribute name { text },
  attribute epoch { text }?,
  attribute version { text },
  attribute release { text },
  attribute arch { text },
  element delta  { 
    attribute oldepoch { text }?,
    attribute oldversion { text }?,
    attribute oldrelease { text }?,
    element filename { text },
    element sequence { text },
    element size { text },
    element checksum {
      attribute type { "sha" | "md5" },
      text
    }
  }+
}