src/Pure/Thy/sessions.scala

       read_properties(db, name, Session_Info.ml_statistics)
 
     def read_task_statistics(db: SQL.Database, name: String): List[Properties.T] =
       read_properties(db, name, Session_Info.task_statistics)
 
+    def read_theories(db: SQL.Database, name: String): List[String] =
+      read_theory_timings(db, name).flatMap(Markup.Name.unapply)
+
     def read_errors(db: SQL.Database, name: String): List[String] =
       Build_Log.uncompress_errors(read_bytes(db, name, Session_Info.errors), cache = xz_cache)
 
     def read_build(db: SQL.Database, name: String): Option[Build.Session_Info] =
     {