diff --git a/src/Pure/Admin/afp.scala b/src/Pure/Admin/afp.scala
--- a/src/Pure/Admin/afp.scala
+++ b/src/Pure/Admin/afp.scala
@@ -1,108 +1,108 @@
 /*  Title:      Pure/Admin/afp.scala
     Author:     Makarius
 
 Administrative support for the Archive of Formal Proofs.
 */
 
 package isabelle
 
 
 object AFP
 {
-  val repos_source = "https://bitbucket.org/isa-afp/afp-devel"
+  val repos_source = "https://isabelle.sketis.net/repos/afp-devel"
 
   val groups: Map[String, String] =
     Map("large" -> "full 64-bit memory model or word arithmetic required",
       "slow" -> "CPU time much higher than 60min (on mid-range hardware)",
       "very_slow" -> "elapsed time of many hours (on high-end hardware)")
 
   def groups_bulky: List[String] = List("large", "slow")
 
   def init(options: Options, base_dir: Path = Path.explode("$AFP_BASE")): AFP =
     new AFP(options, base_dir)
 
   sealed case class Entry(name: String, sessions: List[String])
 }
 
 class AFP private(options: Options, val base_dir: Path)
 {
   override def toString: String = base_dir.expand.toString
 
   val main_dir: Path = base_dir + Path.explode("thys")
 
 
   /* entries and sessions */
 
   val entries: List[AFP.Entry] =
     (for (name <- Sessions.parse_roots(main_dir + Sessions.ROOTS)) yield {
       val sessions =
         Sessions.parse_root_entries(main_dir + Path.explode(name) + Sessions.ROOT).map(_.name)
       AFP.Entry(name, sessions)
     }).sortBy(_.name)
 
   val sessions: List[String] = entries.flatMap(_.sessions)
 
   val sessions_structure: Sessions.Structure =
     Sessions.load_structure(options, dirs = List(main_dir)).
       selection(Sessions.Selection(sessions = sessions.toList))
 
 
   /* dependency graph */
 
   private def sessions_deps(entry: AFP.Entry): List[String] =
     entry.sessions.flatMap(sessions_structure.imports_graph.imm_preds(_)).distinct.sorted
 
   lazy val entries_graph: Graph[String, Unit] =
   {
     val session_entries =
       (Map.empty[String, String] /: entries) {
         case (m1, e) => (m1 /: e.sessions) { case (m2, s) => m2 + (s -> e.name) }
       }
     (Graph.empty[String, Unit] /: entries) { case (g, entry) =>
       val e1 = entry.name
       (g.default_node(e1, ()) /: sessions_deps(entry)) { case (g1, s) =>
         (g1 /: session_entries.get(s).filterNot(_ == e1)) { case (g2, e2) =>
           try { g2.default_node(e2, ()).add_edge_acyclic(e2, e1) }
           catch {
             case exn: Graph.Cycles[_] =>
               error(cat_lines(exn.cycles.map(cycle =>
                 "Cyclic dependency of " + cycle.map(c => quote(c.toString)).mkString(" via ") +
                 " due to session " + quote(s))))
           }
         }
       }
     }
   }
 
   def entries_graph_display: Graph_Display.Graph =
     Graph_Display.make_graph(entries_graph)
 
   def entries_json_text: String =
     (for (entry <- entries.iterator) yield {
       val distrib_deps = sessions_deps(entry).filterNot(sessions.contains(_))
       val afp_deps = entries_graph.imm_preds(entry.name).toList
       """
  {""" + JSON.Format(entry.name) + """:
   {"distrib_deps": """ + JSON.Format(distrib_deps) + """,
    "afp_deps": """ + JSON.Format(afp_deps) + """
   }
  }"""
     }).mkString("[", ", ", "\n]\n")
 
 
   /* partition sessions */
 
   val force_partition1: List[String] = List("Category3", "HOL-ODE")
 
   def partition(n: Int): List[String] =
     n match {
       case 0 => Nil
       case 1 | 2 =>
         val graph = sessions_structure.build_graph.restrict(sessions.toSet)
         val force_part1 =
           graph.all_preds(graph.all_succs(force_partition1.filter(graph.defined(_)))).toSet
         val (part1, part2) = graph.keys.partition(a => force_part1(a) || graph.is_isolated(a))
         if (n == 1) part1 else part2
       case _ => error("Bad AFP partition: " + n + " (should be 0, 1, 2)")
     }
 }