tuned signature;

--- a/src/Pure/Tools/build_stats.scala	Sat Oct 08 15:39:42 2016 +0200
+++ b/src/Pure/Tools/build_stats.scala	Sat Oct 08 15:45:47 2016 +0200
@@ -29,7 +29,7 @@
 
     val all_infos =
       Par_List.map((job_info: CI_API.Job_Info) =>
-        (job_info.timestamp / 1000, job_info.read_output.parse_build_info), job_infos)
+        (job_info.timestamp / 1000, job_info.read_main_log.parse_build_info), job_infos)
     val all_sessions =
       (Set.empty[String] /: all_infos)(
         { case (s, (_, info)) => s ++ info.sessions.keySet })

--- a/src/Pure/Tools/ci_api.scala	Sat Oct 08 15:39:42 2016 +0200
+++ b/src/Pure/Tools/ci_api.scala	Sat Oct 08 15:45:47 2016 +0200
@@ -44,8 +44,8 @@
     output: URL,
     session_logs: List[(String, URL)])
   {
-    def read_output(): Build_Log.Log_File = Build_Log.Log_File(job_name, Url.read(output))
-    def read_log_file(name: String): Build_Log.Log_File =
+    def read_main_log(): Build_Log.Log_File = Build_Log.Log_File(job_name, Url.read(output))
+    def read_session_log(name: String): Build_Log.Log_File =
       Build_Log.Log_File(name,
         session_logs.collectFirst({ case (a, b) if a == name => Url.read_gzip(b) }) getOrElse "")
   }