diff --git a/src/Pure/Thy/export_theory.ML b/src/Pure/Thy/export_theory.ML
--- a/src/Pure/Thy/export_theory.ML
+++ b/src/Pure/Thy/export_theory.ML
@@ -1,422 +1,422 @@
 (*  Title:      Pure/Thy/export_theory.ML
     Author:     Makarius
 
 Export foundational theory content and locale/class structure.
 *)
 
 signature EXPORT_THEORY =
 sig
   val setup_presentation: (Thy_Info.presentation_context -> theory -> unit) -> unit
   val export_body: theory -> string -> XML.body -> unit
 end;
 
 structure Export_Theory: EXPORT_THEORY =
 struct
 
 (* approximative syntax *)
 
 val get_syntax = Syntax.get_approx o Proof_Context.syn_of;
 fun get_syntax_type ctxt = get_syntax ctxt o Lexicon.mark_type;
 fun get_syntax_const ctxt = get_syntax ctxt o Lexicon.mark_const;
 fun get_syntax_fixed ctxt = get_syntax ctxt o Lexicon.mark_fixed;
 
 fun get_syntax_param ctxt loc x =
   let val thy = Proof_Context.theory_of ctxt in
     if Class.is_class thy loc then
       (case AList.lookup (op =) (Class.these_params thy [loc]) x of
         NONE => NONE
       | SOME (_, (c, _)) => get_syntax_const ctxt c)
     else get_syntax_fixed ctxt x
   end;
 
 val encode_syntax =
   XML.Encode.variant
    [fn NONE => ([], []),
     fn SOME (Syntax.Prefix delim) => ([delim], []),
     fn SOME (Syntax.Infix {assoc, delim, pri}) =>
       let
         val ass =
           (case assoc of
             Printer.No_Assoc => 0
           | Printer.Left_Assoc => 1
           | Printer.Right_Assoc => 2);
         open XML.Encode Term_XML.Encode;
       in ([], triple int string int (ass, delim, pri)) end];
 
 
 (* free variables: not declared in the context *)
 
 val is_free = not oo Name.is_declared;
 
 fun add_frees used =
   fold_aterms (fn Free (x, T) => is_free used x ? insert (op =) (x, T) | _ => I);
 
 fun add_tfrees used =
   (fold_types o fold_atyps) (fn TFree (a, S) => is_free used a ? insert (op =) (a, S) | _ => I);
 
 
 (* spec rules *)
 
 fun primrec_types ctxt const =
   Spec_Rules.retrieve ctxt (Const const)
   |> get_first
     (fn (Spec_Rules.Equational (Spec_Rules.Primrec types), _) => SOME (types, false)
       | (Spec_Rules.Equational (Spec_Rules.Primcorec types), _) => SOME (types, true)
       | _ => NONE)
   |> the_default ([], false);
 
 
 (* locales content *)
 
 fun locale_content thy loc =
   let
     val ctxt = Locale.init loc thy;
     val args =
       Locale.params_of thy loc
       |> map (fn ((x, T), _) => ((x, T), get_syntax_param ctxt loc x));
     val axioms =
       let
         val (asm, defs) = Locale.specification_of thy loc;
         val cprops = map (Thm.cterm_of ctxt) (the_list asm @ defs);
         val (intro1, intro2) = Locale.intros_of thy loc;
         val intros_tac = Method.try_intros_tac ctxt (the_list intro1 @ the_list intro2) [];
         val res =
           Goal.init (Conjunction.mk_conjunction_balanced cprops)
           |> (ALLGOALS Goal.conjunction_tac THEN intros_tac)
           |> try Seq.hd;
       in
         (case res of
           SOME goal => Thm.prems_of goal
         | NONE => raise Fail ("Cannot unfold locale " ^ quote loc))
       end;
     val typargs = rev (fold Term.add_tfrees (map (Free o #1) args @ axioms) []);
   in {typargs = typargs, args = args, axioms = axioms} end;
 
 fun get_locales thy =
   Locale.get_locales thy |> map_filter (fn loc =>
     if Experiment.is_experiment thy loc then NONE else SOME (loc, ()));
 
 fun get_dependencies prev_thys thy =
   Locale.dest_dependencies prev_thys thy |> map_filter (fn dep =>
     if Experiment.is_experiment thy (#source dep) orelse
       Experiment.is_experiment thy (#target dep) then NONE
     else
       let
         val (type_params, params) = Locale.parameters_of thy (#source dep);
         val typargs = fold (Term.add_tfreesT o #2 o #1) params type_params;
         val substT =
           typargs |> map_filter (fn v =>
             let
               val T = TFree v;
               val T' = Morphism.typ (#morphism dep) T;
             in if T = T' then NONE else SOME (v, T') end);
         val subst =
           params |> map_filter (fn (v, _) =>
             let
               val t = Free v;
               val t' = Morphism.term (#morphism dep) t;
             in if t aconv t' then NONE else SOME (v, t') end);
       in SOME (dep, (substT, subst)) end);
 
 
 (* general setup *)
 
 fun setup_presentation f =
   Theory.setup (Thy_Info.add_presentation (fn context => fn thy =>
     if Options.bool (#options context) "export_theory" then f context thy else ()));
 
 fun export_buffer thy name buffer =
   if Buffer.is_empty buffer then ()
   else Export.export thy (Path.binding0 (Path.make ["theory", name])) (Buffer.chunks buffer);
 
 fun export_body thy name elems =
   export_buffer thy name (YXML.buffer_body elems Buffer.empty);
 
 
 (* presentation *)
 
 val _ = setup_presentation (fn {adjust_pos, ...} => fn thy =>
   let
     val parents = Theory.parents_of thy;
     val rep_tsig = Type.rep_tsig (Sign.tsig_of thy);
 
     val thy_ctxt = Proof_Context.init_global thy;
 
 
     (* entities *)
 
     fun make_entity_markup name xname pos serial =
       let
         val props =
           Position.offset_properties_of (adjust_pos pos) @
           Position.id_properties_of pos @
           Markup.serial_properties serial;
       in (Markup.entityN, (Markup.nameN, name) :: (Markup.xnameN, xname) :: props) end;
 
     fun entity_markup space name =
       let
         val xname = Name_Space.extern_shortest thy_ctxt space name;
         val {serial, pos, ...} = Name_Space.the_entry space name;
       in make_entity_markup name xname pos serial end;
 
     fun export_entities export_name export get_space decls =
       let
         val parent_spaces = map get_space parents;
         val space = get_space thy;
       in
         (decls, []) |-> fold (fn (name, decl) =>
           if exists (fn space => Name_Space.declared space name) parent_spaces then I
           else
             (case export name decl of
               NONE => I
             | SOME body =>
                 cons (#serial (Name_Space.the_entry space name),
                   XML.Elem (entity_markup space name, body))))
         |> sort (int_ord o apply2 #1) |> map #2
         |> export_body thy export_name
       end;
 
 
     (* types *)
 
     val encode_type =
       let open XML.Encode Term_XML.Encode
       in triple encode_syntax (list string) (option typ) end;
 
     fun export_type c (Type.LogicalType n) =
           SOME (encode_type (get_syntax_type thy_ctxt c, Name.invent Name.context Name.aT n, NONE))
       | export_type c (Type.Abbreviation (args, U, false)) =
           SOME (encode_type (get_syntax_type thy_ctxt c, args, SOME U))
       | export_type _ _ = NONE;
 
     val _ =
       export_entities "types" export_type Sign.type_space
         (Name_Space.dest_table (#types rep_tsig));
 
 
     (* consts *)
 
     val consts = Sign.consts_of thy;
     val encode_term = Term_XML.Encode.term consts;
 
     val encode_const =
       let open XML.Encode Term_XML.Encode in
         pair encode_syntax
           (pair (list string)
             (pair typ (pair (option encode_term) (pair bool (pair (list string) bool)))))
       end;
 
     fun export_const c (T, abbrev) =
       let
         val syntax = get_syntax_const thy_ctxt c;
         val U = Logic.unvarifyT_global T;
         val U0 = Type.strip_sorts U;
         val recursion = primrec_types thy_ctxt (c, U);
         val abbrev' = abbrev
           |> Option.map (Proofterm.standard_vars_term Name.context #> map_types Type.strip_sorts);
         val args = map (#1 o dest_TFree) (Consts.typargs consts (c, U0));
         val propositional = Object_Logic.is_propositional thy_ctxt (Term.body_type U0);
       in encode_const (syntax, (args, (U0, (abbrev', (propositional, recursion))))) end;
 
     val _ =
       export_entities "consts" (SOME oo export_const) Sign.const_space
         (#constants (Consts.dest consts));
 
 
     (* axioms *)
 
     fun standard_prop used extra_shyps raw_prop raw_proof =
       let
         val (prop, proof) = Proofterm.standard_vars used (raw_prop, raw_proof);
         val args = rev (add_frees used prop []);
         val typargs = rev (add_tfrees used prop []);
         val used_typargs = fold (Name.declare o #1) typargs used;
         val sorts = Name.invent used_typargs Name.aT (length extra_shyps) ~~ extra_shyps;
       in ((sorts @ typargs, args, prop), proof) end;
 
     val encode_prop =
       let open XML.Encode Term_XML.Encode
       in triple (list (pair string sort)) (list (pair string typ)) encode_term end;
 
     fun encode_axiom used prop =
       encode_prop (#1 (standard_prop used [] prop NONE));
 
     val _ =
       export_entities "axioms" (K (SOME o encode_axiom Name.context))
         Theory.axiom_space (Theory.all_axioms_of thy);
 
 
     (* theorems and proof terms *)
 
     val export_standard_proofs = Options.default_bool @{system_option export_standard_proofs};
 
     val clean_thm = Thm.check_hyps (Context.Theory thy) #> Thm.strip_shyps;
 
     val lookup_thm_id = Global_Theory.lookup_thm_id thy;
 
     fun proof_boxes_of thm thm_id =
-      (Thm_Deps.proof_boxes
+      (Thm_Deps.thm_boxes
         {included = fn thm_id' => #serial thm_id = #serial thm_id',
          excluded = is_some o lookup_thm_id} [thm]) @ [thm_id];
 
     fun expand_name thm_id (header: Proofterm.thm_header) =
       if #serial header = #serial thm_id then ""
       else
         (case lookup_thm_id (Proofterm.thm_header_id header) of
           NONE => ""
         | SOME thm_name => Thm_Name.print thm_name);
 
     fun entity_markup_thm (serial, (name, i)) =
       let
         val space = Facts.space_of (Global_Theory.facts_of thy);
         val xname = Name_Space.extern_shortest thy_ctxt space name;
         val {pos, ...} = Name_Space.the_entry space name;
       in make_entity_markup (Thm_Name.print (name, i)) (Thm_Name.print (xname, i)) pos serial end;
 
     fun encode_thm thm_id raw_thm =
       let
         val deps = map (Thm_Name.print o #2) (Thm_Deps.thm_deps thy [raw_thm]);
         val thm = clean_thm (Thm.unconstrainT raw_thm);
         val boxes = proof_boxes_of thm thm_id;
 
         val proof0 =
           if export_standard_proofs then
             Thm.standard_proof_of {full = true, expand_name = SOME o expand_name thm_id} thm
           else if Proofterm.export_enabled () then Thm.reconstruct_proof_of thm
           else MinProof;
         val (prop, SOME proof) =
           standard_prop Name.context (Thm.extra_shyps thm) (Thm.full_prop_of thm) (SOME proof0);
         val _ = Proofterm.commit_proof proof;
       in
         (prop, (deps, (boxes, proof))) |>
           let
             open XML.Encode Term_XML.Encode;
             fun encode_box {serial, theory_name} = pair int string (serial, theory_name);
             val encode_proof = Proofterm.encode_standard_proof consts;
           in pair encode_prop (pair (list string) (pair (list encode_box) encode_proof)) end
       end;
 
     fun buffer_export_thm (thm_id, thm_name) =
       let
         val markup = entity_markup_thm (#serial thm_id, thm_name);
         val thm = Global_Theory.get_thm_name thy (thm_name, Position.none);
         val body = encode_thm thm_id thm;
       in YXML.buffer (XML.Elem (markup, body)) end;
 
     val _ =
       Buffer.empty
       |> fold buffer_export_thm (Global_Theory.dest_thm_names thy)
       |> export_buffer thy "thms";
 
 
     (* type classes *)
 
     val encode_class =
       let open XML.Encode Term_XML.Encode
       in pair (list (pair string typ)) (list (encode_axiom Name.context)) end;
 
     fun export_class name =
       (case try (Axclass.get_info thy) name of
         NONE => ([], [])
       | SOME {params, axioms, ...} => (params, map (Thm.plain_prop_of o clean_thm) axioms))
       |> encode_class |> SOME;
 
     val _ =
       export_entities "classes" (fn name => fn () => export_class name)
         Sign.class_space (map (rpair ()) (Graph.keys (Sorts.classes_of (#2 (#classes rep_tsig)))));
 
 
     (* sort algebra *)
 
     local
       val prop = encode_axiom Name.context o Logic.varify_global;
 
       val encode_classrel =
         let open XML.Encode
         in list (pair prop (pair string string)) end;
 
       val encode_arities =
         let open XML.Encode Term_XML.Encode
         in list (pair prop (triple string (list sort) string)) end;
     in
       val export_classrel =
         maps (fn (c, cs) => map (pair c) cs) #> map (`Logic.mk_classrel) #> encode_classrel;
 
       val export_arities = map (`Logic.mk_arity) #> encode_arities;
 
       val {classrel, arities} =
         Sorts.dest_algebra (map (#2 o #classes o Type.rep_tsig o Sign.tsig_of) parents)
           (#2 (#classes rep_tsig));
     end;
 
     val _ = if null classrel then () else export_body thy "classrel" (export_classrel classrel);
     val _ = if null arities then () else export_body thy "arities" (export_arities arities);
 
 
     (* locales *)
 
     fun encode_locale used =
       let open XML.Encode Term_XML.Encode in
         triple (list (pair string sort)) (list (pair (pair string typ) encode_syntax))
           (list (encode_axiom used))
       end;
 
     fun export_locale loc =
       let
         val {typargs, args, axioms} = locale_content thy loc;
         val used = fold Name.declare (map #1 typargs @ map (#1 o #1) args) Name.context;
       in encode_locale used (typargs, args, axioms) end
       handle ERROR msg =>
         cat_error msg ("The error(s) above occurred in locale " ^
           quote (Locale.markup_name thy_ctxt loc));
 
     val _ =
       export_entities "locales" (fn loc => fn () => SOME (export_locale loc))
         Locale.locale_space (get_locales thy);
 
 
     (* locale dependencies *)
 
     fun encode_locale_dependency (dep: Locale.locale_dependency, subst) =
       (#source dep, (#target dep, (#prefix dep, subst))) |>
         let
           open XML.Encode Term_XML.Encode;
           val encode_subst =
             pair (list (pair (pair string sort) typ)) (list (pair (pair string typ) (term consts)));
         in pair string (pair string (pair (list (pair string bool)) encode_subst)) end;
 
     val _ =
       get_dependencies parents thy
       |> map_index (fn (i, dep) =>
         let
           val xname = string_of_int (i + 1);
           val name = Long_Name.implode [Context.theory_name thy, xname];
           val markup = make_entity_markup name xname (#pos (#1 dep)) (#serial (#1 dep));
           val body = encode_locale_dependency dep;
         in XML.Elem (markup, body) end)
       |> export_body thy "locale_dependencies";
 
 
     (* constdefs *)
 
     val constdefs =
       Defs.dest_constdefs (map Theory.defs_of (Theory.parents_of thy)) (Theory.defs_of thy)
       |> sort_by #1;
 
     val encode_constdefs =
       let open XML.Encode
       in list (pair string string) end;
 
     val _ =
       if null constdefs then () else export_body thy "constdefs" (encode_constdefs constdefs);
 
 
     (* parents *)
 
     val _ =
       Export.export thy \<^path_binding>\<open>theory/parents\<close>
         [YXML.string_of_body (XML.Encode.string (cat_lines (map Context.theory_long_name parents)))];
 
   in () end);
 
 end;
diff --git a/src/Pure/thm_deps.ML b/src/Pure/thm_deps.ML
--- a/src/Pure/thm_deps.ML
+++ b/src/Pure/thm_deps.ML
@@ -1,152 +1,152 @@
 (*  Title:      Pure/thm_deps.ML
     Author:     Stefan Berghofer, TU Muenchen
     Author:     Makarius
 
 Dependencies of theorems wrt. internal derivation.
 *)
 
 signature THM_DEPS =
 sig
   val all_oracles: thm list -> Proofterm.oracle list
   val has_skip_proof: thm list -> bool
   val pretty_thm_oracles: Proof.context -> thm list -> Pretty.T
   val thm_deps: theory -> thm list -> (Proofterm.thm_id * Thm_Name.T) list
   val pretty_thm_deps: theory -> thm list -> Pretty.T
-  val proof_boxes: {included: Proofterm.thm_id -> bool, excluded: Proofterm.thm_id -> bool} ->
+  val thm_boxes: {included: Proofterm.thm_id -> bool, excluded: Proofterm.thm_id -> bool} ->
     thm list -> Proofterm.thm_id list
   val unused_thms_cmd: theory list * theory list -> (string * thm) list
 end;
 
 structure Thm_Deps: THM_DEPS =
 struct
 
 (* oracles *)
 
 fun all_oracles thms =
   let
     fun collect (PBody {oracles, thms, ...}) =
       (if null oracles then I else apfst (cons oracles)) #>
       (tap Proofterm.join_thms thms |> fold (fn (i, thm_node) => fn (res, seen) =>
         if Inttab.defined seen i then (res, seen)
         else
           let val body = Future.join (Proofterm.thm_node_body thm_node)
           in collect body (res, Inttab.update (i, ()) seen) end));
     val bodies = map Thm.proof_body_of thms;
   in fold collect bodies ([], Inttab.empty) |> #1 |> Proofterm.unions_oracles end;
 
 fun has_skip_proof thms =
   all_oracles thms |> exists (fn (name, _) => name = \<^oracle_name>\<open>skip_proof\<close>);
 
 fun pretty_thm_oracles ctxt thms =
   let
     val thy = Proof_Context.theory_of ctxt;
     fun prt_oracle (name, NONE) = [Thm.pretty_oracle ctxt name]
       | prt_oracle (name, SOME prop) =
           [Thm.pretty_oracle ctxt name, Pretty.str ":", Pretty.brk 1,
             Syntax.pretty_term_global thy prop];
   in Pretty.big_list "oracles:" (map (Pretty.item o prt_oracle) (all_oracles thms)) end;
 
 
 (* thm_deps *)
 
 fun thm_deps thy =
   let
     val lookup = Global_Theory.lookup_thm_id thy;
     fun deps (i, thm_node) res =
       if Inttab.defined res i then res
       else
         let val thm_id = Proofterm.thm_id (i, thm_node) in
           (case lookup thm_id of
             SOME thm_name =>
               Inttab.update (i, SOME (thm_id, thm_name)) res
           | NONE =>
               Inttab.update (i, NONE) res
               |> fold deps (Proofterm.thm_node_thms thm_node))
         end;
   in
     fn thms =>
       (fold (fold deps o Thm.thm_deps o Thm.transfer thy) thms Inttab.empty, [])
       |-> Inttab.fold_rev (fn (_, SOME entry) => cons entry | _ => I)
   end;
 
 fun pretty_thm_deps thy thms =
   let
     val ctxt = Proof_Context.init_global thy;
     val items =
       map #2 (thm_deps thy thms)
       |> map (fn (name, i) => (Proof_Context.markup_extern_fact ctxt name, i))
       |> sort_by (#2 o #1)
       |> map (fn ((marks, xname), i) =>
           Pretty.item [Pretty.marks_str (marks, Thm_Name.print (xname, i))]);
   in Pretty.big_list ("dependencies: " ^ string_of_int (length items)) items end;
 
 
-(* proof boxes: undefined PThm nodes *)
+(* thm boxes: intermediate PThm nodes *)
 
-fun proof_boxes {included, excluded} thms =
+fun thm_boxes {included, excluded} thms =
   let
     fun boxes (i, thm_node) res =
       let val thm_id = Proofterm.thm_id (i, thm_node) in
         if Inttab.defined res i orelse (excluded thm_id andalso not (included thm_id))
         then res
         else
           Inttab.update (i, thm_id) res
           |> fold boxes (Proofterm.thm_node_thms thm_node)
       end;
   in Inttab.fold_rev (cons o #2) (fold (fold boxes o Thm.thm_deps) thms Inttab.empty) [] end;
 
 
 (* unused_thms_cmd *)
 
 fun unused_thms_cmd (base_thys, thys) =
   let
     fun add_fact transfer space (name, ths) =
       if exists (fn thy => Global_Theory.defined_fact thy name) base_thys then I
       else
         let val {concealed, group, ...} = Name_Space.the_entry space name in
           fold_rev (fn th =>
             (case Thm.derivation_name th of
               "" => I
             | a => cons (a, (transfer th, concealed, group)))) ths
         end;
     fun add_facts thy =
       let
         val transfer = Global_Theory.transfer_theories thy;
         val facts = Global_Theory.facts_of thy;
       in Facts.fold_static (add_fact transfer (Facts.space_of facts)) facts end;
 
     val new_thms =
       fold add_facts thys []
       |> sort_distinct (string_ord o apply2 #1);
 
     val used =
       Proofterm.fold_body_thms
         (fn {name = a, ...} => a <> "" ? Symtab.update (a, ()))
         (map Proofterm.strip_thm_body (Thm.proof_bodies_of (map (#1 o #2) new_thms)))
         Symtab.empty;
 
     fun is_unused a = not (Symtab.defined used a);
 
     (*groups containing at least one used theorem*)
     val used_groups = fold (fn (a, (_, _, group)) =>
       if is_unused a then I
       else
         (case group of
           NONE => I
         | SOME grp => Inttab.update (grp, ()))) new_thms Inttab.empty;
 
     val (thms', _) = fold (fn (a, (th, concealed, group)) => fn q as (thms, seen_groups) =>
       if not concealed andalso
         (* FIXME replace by robust treatment of thm groups *)
         Thm.legacy_get_kind th = Thm.theoremK andalso is_unused a
       then
         (case group of
            NONE => ((a, th) :: thms, seen_groups)
          | SOME grp =>
              if Inttab.defined used_groups grp orelse
                Inttab.defined seen_groups grp then q
              else ((a, th) :: thms, Inttab.update (grp, ()) seen_groups))
       else q) new_thms ([], Inttab.empty);
   in rev thms' end;
 
 end;