src/Pure/Thy/thy_header.scala

 
   sealed case class Header(val name: String, val imports: List[String], val uses: List[String])
   {
     def map(f: String => String): Header =
       Header(f(name), imports.map(f), uses.map(f))
-  }
-
-  val xml_encode: XML.Encode.T[Header] =
-  {
-    case Header(name, imports, uses) =>
-      import XML.Encode._
-      triple(string, list(string), list(string))(name, imports, uses)
   }
 
 
   /* file name */