discontinued somewhat pointless "integrity test of build_history": it fails right now, but also failed to expose spurious incompatibilities when it was working;
# Default interpretation of some Isabelle symbols
\<zero> code: 0x01d7ec group: digit
\<one> code: 0x01d7ed group: digit
\<two> code: 0x01d7ee group: digit
\<three> code: 0x01d7ef group: digit
\<four> code: 0x01d7f0 group: digit
\<five> code: 0x01d7f1 group: digit
\<six> code: 0x01d7f2 group: digit
\<seven> code: 0x01d7f3 group: digit
\<eight> code: 0x01d7f4 group: digit
\<nine> code: 0x01d7f5 group: digit
\<A> code: 0x01d49c group: letter
\<B> code: 0x00212c group: letter
\<C> code: 0x01d49e group: letter
\<D> code: 0x01d49f group: letter
\<E> code: 0x002130 group: letter
\<F> code: 0x002131 group: letter
\<G> code: 0x01d4a2 group: letter
\<H> code: 0x00210b group: letter
\<I> code: 0x002110 group: letter
\<J> code: 0x01d4a5 group: letter
\<K> code: 0x01d4a6 group: letter
\<L> code: 0x002112 group: letter
\<M> code: 0x002133 group: letter
\<N> code: 0x01d4a9 group: letter
\<O> code: 0x01d4aa group: letter
\<P> code: 0x01d4ab group: letter
\<Q> code: 0x01d4ac group: letter
\<R> code: 0x00211b group: letter
\<S> code: 0x01d4ae group: letter
\<T> code: 0x01d4af group: letter
\<U> code: 0x01d4b0 group: letter
\<V> code: 0x01d4b1 group: letter
\<W> code: 0x01d4b2 group: letter
\<X> code: 0x01d4b3 group: letter
\<Y> code: 0x01d4b4 group: letter
\<Z> code: 0x01d4b5 group: letter
\<a> code: 0x01d5ba group: letter
\<b> code: 0x01d5bb group: letter
\<c> code: 0x01d5bc group: letter
\<d> code: 0x01d5bd group: letter
\<e> code: 0x01d5be group: letter
\<f> code: 0x01d5bf group: letter
\<g> code: 0x01d5c0 group: letter
\<h> code: 0x01d5c1 group: letter
\<i> code: 0x01d5c2 group: letter
\<j> code: 0x01d5c3 group: letter
\<k> code: 0x01d5c4 group: letter
\<l> code: 0x01d5c5 group: letter
\<m> code: 0x01d5c6 group: letter
\<n> code: 0x01d5c7 group: letter
\<o> code: 0x01d5c8 group: letter
\<p> code: 0x01d5c9 group: letter
\<q> code: 0x01d5ca group: letter
\<r> code: 0x01d5cb group: letter
\<s> code: 0x01d5cc group: letter
\<t> code: 0x01d5cd group: letter
\<u> code: 0x01d5ce group: letter
\<v> code: 0x01d5cf group: letter
\<w> code: 0x01d5d0 group: letter
\<x> code: 0x01d5d1 group: letter
\<y> code: 0x01d5d2 group: letter
\<z> code: 0x01d5d3 group: letter
\<AA> code: 0x01d504 group: letter
\<BB> code: 0x01d505 group: letter
\<CC> code: 0x00212d group: letter
\<DD> code: 0x01d507 group: letter
\<EE> code: 0x01d508 group: letter
\<FF> code: 0x01d509 group: letter
\<GG> code: 0x01d50a group: letter
\<HH> code: 0x00210c group: letter
\<II> code: 0x002111 group: letter
\<JJ> code: 0x01d50d group: letter
\<KK> code: 0x01d50e group: letter
\<LL> code: 0x01d50f group: letter
\<MM> code: 0x01d510 group: letter
\<NN> code: 0x01d511 group: letter
\<OO> code: 0x01d512 group: letter
\<PP> code: 0x01d513 group: letter
\<QQ> code: 0x01d514 group: letter
\<RR> code: 0x00211c group: letter
\<SS> code: 0x01d516 group: letter
\<TT> code: 0x01d517 group: letter
\<UU> code: 0x01d518 group: letter
\<VV> code: 0x01d519 group: letter
\<WW> code: 0x01d51a group: letter
\<XX> code: 0x01d51b group: letter
\<YY> code: 0x01d51c group: letter
\<ZZ> code: 0x002128 group: letter
\<aa> code: 0x01d51e group: letter
\<bb> code: 0x01d51f group: letter
\<cc> code: 0x01d520 group: letter
\<dd> code: 0x01d521 group: letter
\<ee> code: 0x01d522 group: letter
\<ff> code: 0x01d523 group: letter
\<gg> code: 0x01d524 group: letter
\<hh> code: 0x01d525 group: letter
\<ii> code: 0x01d526 group: letter
\<jj> code: 0x01d527 group: letter
\<kk> code: 0x01d528 group: letter
\<ll> code: 0x01d529 group: letter
\<mm> code: 0x01d52a group: letter
\<nn> code: 0x01d52b group: letter
\<oo> code: 0x01d52c group: letter
\<pp> code: 0x01d52d group: letter
\<qq> code: 0x01d52e group: letter
\<rr> code: 0x01d52f group: letter
\<ss> code: 0x01d530 group: letter
\<tt> code: 0x01d531 group: letter
\<uu> code: 0x01d532 group: letter
\<vv> code: 0x01d533 group: letter
\<ww> code: 0x01d534 group: letter
\<xx> code: 0x01d535 group: letter
\<yy> code: 0x01d536 group: letter
\<zz> code: 0x01d537 group: letter
\<alpha> code: 0x0003b1 group: greek
\<beta> code: 0x0003b2 group: greek
\<gamma> code: 0x0003b3 group: greek
\<delta> code: 0x0003b4 group: greek
\<epsilon> code: 0x0003b5 group: greek
\<zeta> code: 0x0003b6 group: greek
\<eta> code: 0x0003b7 group: greek
\<theta> code: 0x0003b8 group: greek
\<iota> code: 0x0003b9 group: greek
\<kappa> code: 0x0003ba group: greek
\<lambda> code: 0x0003bb group: greek abbrev: %
\<mu> code: 0x0003bc group: greek
\<nu> code: 0x0003bd group: greek
\<xi> code: 0x0003be group: greek
\<pi> code: 0x0003c0 group: greek
\<rho> code: 0x0003c1 group: greek
\<sigma> code: 0x0003c3 group: greek
\<tau> code: 0x0003c4 group: greek
\<upsilon> code: 0x0003c5 group: greek
\<phi> code: 0x0003c6 group: greek
\<chi> code: 0x0003c7 group: greek
\<psi> code: 0x0003c8 group: greek
\<omega> code: 0x0003c9 group: greek
\<Gamma> code: 0x000393 group: greek
\<Delta> code: 0x000394 group: greek
\<Theta> code: 0x000398 group: greek
\<Lambda> code: 0x00039b group: greek
\<Xi> code: 0x00039e group: greek
\<Pi> code: 0x0003a0 group: greek
\<Sigma> code: 0x0003a3 group: greek
\<Upsilon> code: 0x0003a5 group: greek
\<Phi> code: 0x0003a6 group: greek
\<Psi> code: 0x0003a8 group: greek
\<Omega> code: 0x0003a9 group: greek
\<bool> code: 0x01d539 group: letter
\<complex> code: 0x002102 group: letter
\<nat> code: 0x002115 group: letter
\<rat> code: 0x00211a group: letter
\<real> code: 0x00211d group: letter
\<int> code: 0x002124 group: letter
\<leftarrow> code: 0x002190 group: arrow abbrev: <.
\<longleftarrow> code: 0x0027f5 group: arrow abbrev: <.
\<longlongleftarrow> code: 0x00290e group: arrow abbrev: <.
\<longlonglongleftarrow> code: 0x0021e0 group: arrow abbrev: <.
\<rightarrow> code: 0x002192 group: arrow abbrev: .> abbrev: ->
\<longrightarrow> code: 0x0027f6 group: arrow abbrev: .> abbrev: -->
\<longlongrightarrow> code: 0x00290f group: arrow abbrev: .> abbrev: --->
\<longlonglongrightarrow> code: 0x0021e2 group: arrow abbrev: .> abbrev: --->
\<Leftarrow> code: 0x0021d0 group: arrow abbrev: <.
\<Longleftarrow> code: 0x0027f8 group: arrow abbrev: <.
\<Lleftarrow> code: 0x0021da group: arrow abbrev: <.
\<Rightarrow> code: 0x0021d2 group: arrow abbrev: .> abbrev: =>
\<Longrightarrow> code: 0x0027f9 group: arrow abbrev: .> abbrev: ==>
\<Rrightarrow> code: 0x0021db group: arrow abbrev: .>
\<leftrightarrow> code: 0x002194 group: arrow abbrev: <> abbrev: <->
\<longleftrightarrow> code: 0x0027f7 group: arrow abbrev: <> abbrev: <-> abbrev: <-->
\<Leftrightarrow> code: 0x0021d4 group: arrow abbrev: <>
\<Longleftrightarrow> code: 0x0027fa group: arrow abbrev: <>
\<mapsto> code: 0x0021a6 group: arrow abbrev: .> abbrev: |->
\<longmapsto> code: 0x0027fc group: arrow abbrev: .> abbrev: |-->
\<midarrow> code: 0x002500 group: arrow abbrev: <>
\<Midarrow> code: 0x002550 group: arrow abbrev: <>
\<hookleftarrow> code: 0x0021a9 group: arrow abbrev: <.
\<hookrightarrow> code: 0x0021aa group: arrow abbrev: .>
\<leftharpoondown> code: 0x0021bd group: arrow abbrev: <.
\<rightharpoondown> code: 0x0021c1 group: arrow abbrev: .>
\<leftharpoonup> code: 0x0021bc group: arrow abbrev: <.
\<rightharpoonup> code: 0x0021c0 group: arrow abbrev: .>
\<rightleftharpoons> code: 0x0021cc group: arrow abbrev: <> abbrev: ==
\<leadsto> code: 0x00219d group: arrow abbrev: .> abbrev: ~>
\<downharpoonleft> code: 0x0021c3 group: arrow
\<downharpoonright> code: 0x0021c2 group: arrow
\<upharpoonleft> code: 0x0021bf group: arrow
#\<upharpoonright> code: 0x0021be group: arrow
\<restriction> code: 0x0021be group: operator
\<Colon> code: 0x002237 group: punctuation
\<up> code: 0x002191 group: arrow
\<Up> code: 0x0021d1 group: arrow
\<down> code: 0x002193 group: arrow
\<Down> code: 0x0021d3 group: arrow
\<updown> code: 0x002195 group: arrow
\<Updown> code: 0x0021d5 group: arrow
\<langle> code: 0x0027e8 group: punctuation abbrev: <<
\<rangle> code: 0x0027e9 group: punctuation abbrev: >>
\<llangle> code: 0x0027ea group: punctuation abbrev: <<
\<rrangle> code: 0x0027eb group: punctuation abbrev: >>
\<lceil> code: 0x002308 group: punctuation abbrev: [.
\<rceil> code: 0x002309 group: punctuation abbrev: .]
\<lfloor> code: 0x00230a group: punctuation abbrev: [.
\<rfloor> code: 0x00230b group: punctuation abbrev: .]
\<lparr> code: 0x002987 group: punctuation abbrev: (|
\<rparr> code: 0x002988 group: punctuation abbrev: |)
\<lbrakk> code: 0x0027e6 group: punctuation abbrev: [|
\<rbrakk> code: 0x0027e7 group: punctuation abbrev: |]
\<lbrace> code: 0x002983 group: punctuation abbrev: {|
\<rbrace> code: 0x002984 group: punctuation abbrev: |}
\<guillemotleft> code: 0x0000ab group: punctuation abbrev: <<
\<guillemotright> code: 0x0000bb group: punctuation abbrev: >>
\<bottom> code: 0x0022a5 group: logic
\<top> code: 0x0022a4 group: logic
\<and> code: 0x002227 group: logic abbrev: /\ abbrev: &
\<And> code: 0x0022c0 group: logic abbrev: !!
\<or> code: 0x002228 group: logic abbrev: \/ abbrev: |
\<Or> code: 0x0022c1 group: logic abbrev: ??
\<forall> code: 0x002200 group: logic abbrev: ! abbrev: ALL
\<exists> code: 0x002203 group: logic abbrev: ? abbrev: EX
\<nexists> code: 0x002204 group: logic abbrev: ~?
\<not> code: 0x0000ac group: logic abbrev: ~
\<circle> code: 0x0025cb group: logic
\<box> code: 0x0025a1 group: logic
\<diamond> code: 0x0025c7 group: logic
\<diamondop> code: 0x0022c4 group: operator
\<turnstile> code: 0x0022a2 group: relation abbrev: |-
\<Turnstile> code: 0x0022a8 group: relation abbrev: |=
\<tturnstile> code: 0x0022a9 group: relation abbrev: |-
\<TTurnstile> code: 0x0022ab group: relation abbrev: |=
\<stileturn> code: 0x0022a3 group: relation abbrev: -|
\<surd> code: 0x00221a group: relation
\<le> code: 0x002264 group: relation abbrev: <=
\<ge> code: 0x002265 group: relation abbrev: >=
\<lless> code: 0x00226a group: relation abbrev: <<
\<ggreater> code: 0x00226b group: relation abbrev: >>
\<lesssim> code: 0x002272 group: relation
\<greatersim> code: 0x002273 group: relation
\<lessapprox> code: 0x002a85 group: relation
\<greaterapprox> code: 0x002a86 group: relation
\<in> code: 0x002208 group: relation abbrev: :
\<notin> code: 0x002209 group: relation abbrev: ~:
\<subset> code: 0x002282 group: relation
\<supset> code: 0x002283 group: relation
\<subseteq> code: 0x002286 group: relation abbrev: (=
\<supseteq> code: 0x002287 group: relation abbrev: )=
\<sqsubset> code: 0x00228f group: relation
\<sqsupset> code: 0x002290 group: relation
\<sqsubseteq> code: 0x002291 group: relation abbrev: [=
\<sqsupseteq> code: 0x002292 group: relation abbrev: ]=
\<inter> code: 0x002229 group: operator abbrev: Int
\<Inter> code: 0x0022c2 group: operator abbrev: Inter abbrev: INT
\<union> code: 0x00222a group: operator abbrev: Un
\<Union> code: 0x0022c3 group: operator abbrev: Union abbrev: UN
\<squnion> code: 0x002294 group: operator
\<Squnion> code: 0x002a06 group: operator abbrev: SUP
\<sqinter> code: 0x002293 group: operator
\<Sqinter> code: 0x002a05 group: operator abbrev: INF
\<setminus> code: 0x002216 group: operator
\<propto> code: 0x00221d group: operator
\<uplus> code: 0x00228e group: operator
\<Uplus> code: 0x002a04 group: operator
\<noteq> code: 0x002260 group: relation abbrev: ~=
\<sim> code: 0x00223c group: relation
\<doteq> code: 0x002250 group: relation abbrev: .=
\<simeq> code: 0x002243 group: relation
\<approx> code: 0x002248 group: relation
\<asymp> code: 0x00224d group: relation
\<cong> code: 0x002245 group: relation
\<smile> code: 0x002323 group: relation
\<equiv> code: 0x002261 group: relation abbrev: ==
\<frown> code: 0x002322 group: relation
\<Join> code: 0x0022c8
\<bowtie> code: 0x002a1d
\<prec> code: 0x00227a group: relation
\<succ> code: 0x00227b group: relation
\<preceq> code: 0x00227c group: relation
\<succeq> code: 0x00227d group: relation
\<parallel> code: 0x002225 group: punctuation abbrev: ||
\<bar> code: 0x0000a6 group: punctuation abbrev: ||
\<bbar> code: 0x002aff group: punctuation abbrev: ||
\<plusminus> code: 0x0000b1 group: operator
\<minusplus> code: 0x002213 group: operator
\<times> code: 0x0000d7 group: operator abbrev: <*>
\<div> code: 0x0000f7 group: operator
\<cdot> code: 0x0022c5 group: operator
\<star> code: 0x0022c6 group: operator
\<bullet> code: 0x002219 group: operator
\<circ> code: 0x002218 group: operator
\<dagger> code: 0x002020
\<ddagger> code: 0x002021
\<lhd> code: 0x0022b2 group: relation
\<rhd> code: 0x0022b3 group: relation
\<unlhd> code: 0x0022b4 group: relation
\<unrhd> code: 0x0022b5 group: relation
\<triangleleft> code: 0x0025c3 group: relation
\<triangleright> code: 0x0025b9 group: relation
\<triangle> code: 0x0025b3 group: relation
\<triangleq> code: 0x00225c group: relation
\<oplus> code: 0x002295 group: operator
\<Oplus> code: 0x002a01 group: operator
\<otimes> code: 0x002297 group: operator
\<Otimes> code: 0x002a02 group: operator
\<odot> code: 0x002299 group: operator
\<Odot> code: 0x002a00 group: operator
\<ominus> code: 0x002296 group: operator
\<oslash> code: 0x002298 group: operator
\<dots> code: 0x002026 group: punctuation abbrev: ...
\<cdots> code: 0x0022ef group: punctuation
\<Sum> code: 0x002211 group: operator abbrev: SUM
\<Prod> code: 0x00220f group: operator abbrev: PROD
\<Coprod> code: 0x002210 group: operator
\<infinity> code: 0x00221e
\<integral> code: 0x00222b group: operator
\<ointegral> code: 0x00222e group: operator
\<clubsuit> code: 0x002663
\<diamondsuit> code: 0x002662
\<heartsuit> code: 0x002661
\<spadesuit> code: 0x002660
\<aleph> code: 0x002135
\<emptyset> code: 0x002205
\<nabla> code: 0x002207
\<partial> code: 0x002202
\<flat> code: 0x00266d
\<natural> code: 0x00266e
\<sharp> code: 0x00266f
\<angle> code: 0x002220
\<copyright> code: 0x0000a9
\<registered> code: 0x0000ae
\<hyphen> code: 0x002010 group: punctuation
\<inverse> code: 0x0000af group: operator
\<sqdot> code: 0x0000b7 group: punctuation
\<onequarter> code: 0x0000bc group: digit
\<onehalf> code: 0x0000bd group: digit
\<threequarters> code: 0x0000be group: digit
\<ordfeminine> code: 0x0000aa
\<ordmasculine> code: 0x0000ba
\<section> code: 0x0000a7
\<paragraph> code: 0x0000b6
\<exclamdown> code: 0x0000a1
\<questiondown> code: 0x0000bf
\<euro> code: 0x0020ac
\<pounds> code: 0x0000a3
\<yen> code: 0x0000a5
\<cent> code: 0x0000a2
\<currency> code: 0x0000a4
\<degree> code: 0x0000b0
\<amalg> code: 0x002a3f group: operator
\<mho> code: 0x002127 group: operator
\<lozenge> code: 0x0025ca
\<wp> code: 0x002118
\<wrong> code: 0x002240 group: relation
\<acute> code: 0x0000b4
\<index> code: 0x000131
\<dieresis> code: 0x0000a8
\<cedilla> code: 0x0000b8
\<hungarumlaut> code: 0x0002dd
\<bind> code: 0x00291c group: operator abbrev: >>=
\<then> code: 0x002aa2 group: operator abbrev: >>
\<some> code: 0x0003f5
\<hole> code: 0x002311
\<newline> code: 0x0023ce
\<comment> code: 0x002015 group: document argument: space_cartouche font: Isabelle␣DejaVu␣Sans␣Mono
\<^cancel> code: 0x002326 group: document argument: cartouche font: Isabelle␣DejaVu␣Sans␣Mono
\<^latex> group: document argument: cartouche
\<^marker> code: 0x002710 group: document argument: cartouche font: Isabelle␣DejaVu␣Sans␣Mono
\<open> code: 0x002039 group: punctuation font: Isabelle␣DejaVu␣Sans␣Mono abbrev: <<
\<close> code: 0x00203a group: punctuation font: Isabelle␣DejaVu␣Sans␣Mono abbrev: >>
\<^here> code: 0x002302 font: Isabelle␣DejaVu␣Sans␣Mono
\<^undefined> code: 0x002756 font: Isabelle␣DejaVu␣Sans␣Mono
\<^noindent> code: 0x0021e4 group: document font: Isabelle␣DejaVu␣Sans␣Mono
\<^smallskip> code: 0x002508 group: document font: Isabelle␣DejaVu␣Sans␣Mono
\<^medskip> code: 0x002509 group: document font: Isabelle␣DejaVu␣Sans␣Mono
\<^bigskip> code: 0x002501 group: document font: Isabelle␣DejaVu␣Sans␣Mono
\<^item> code: 0x0025aa group: document font: Isabelle␣DejaVu␣Sans␣Mono
\<^enum> code: 0x0025b8 group: document font: Isabelle␣DejaVu␣Sans␣Mono
\<^descr> code: 0x0027a7 group: document font: Isabelle␣DejaVu␣Sans␣Mono
\<^footnote> code: 0x00204b group: document argument: cartouche font: Isabelle␣DejaVu␣Sans␣Mono
\<^verbatim> code: 0x0025a9 group: document argument: cartouche font: Isabelle␣DejaVu␣Sans␣Mono
\<^theory_text> code: 0x002b1a group: document argument: cartouche font: Isabelle␣DejaVu␣Sans␣Mono
\<^emph> code: 0x002217 group: document argument: cartouche font: Isabelle␣DejaVu␣Sans␣Mono
\<^bold> code: 0x002759 group: control argument: cartouche group: document font: Isabelle␣DejaVu␣Sans␣Mono
\<^sub> code: 0x0021e9 group: control font: Isabelle␣DejaVu␣Sans␣Mono
\<^sup> code: 0x0021e7 group: control font: Isabelle␣DejaVu␣Sans␣Mono
\<^bsub> code: 0x0021d8 group: control_block font: Isabelle␣DejaVu␣Sans␣Mono abbrev: =_(
\<^esub> code: 0x0021d9 group: control_block font: Isabelle␣DejaVu␣Sans␣Mono abbrev: =_)
\<^bsup> code: 0x0021d7 group: control_block font: Isabelle␣DejaVu␣Sans␣Mono abbrev: =^(
\<^esup> code: 0x0021d6 group: control_block font: Isabelle␣DejaVu␣Sans␣Mono abbrev: =^)
\<^file> code: 0x01F5CF group: icon argument: cartouche font: Isabelle␣DejaVu␣Sans␣Mono
\<^dir> code: 0x01F5C0 group: icon argument: cartouche font: Isabelle␣DejaVu␣Sans␣Mono
\<^url> code: 0x01F310 group: icon argument: cartouche font: Isabelle␣DejaVu␣Sans␣Mono
\<^doc> code: 0x01F4D3 group: icon argument: cartouche font: Isabelle␣DejaVu␣Sans␣Mono
\<^action> code: 0x00261b group: icon argument: cartouche font: Isabelle␣DejaVu␣Sans␣Mono
\<^assert>
\<^binding> argument: cartouche
\<^class> argument: cartouche
\<^class_syntax> argument: cartouche
\<^command_keyword> argument: cartouche
\<^const> argument: cartouche
\<^const_abbrev> argument: cartouche
\<^const_name> argument: cartouche
\<^const_syntax> argument: cartouche
\<^context>
\<^cprop> argument: cartouche
\<^cterm> argument: cartouche
\<^ctyp> argument: cartouche
\<^keyword> argument: cartouche
\<^locale> argument: cartouche
\<^make_string>
\<^method> argument: cartouche
\<^named_theorems> argument: cartouche
\<^nonterminal> argument: cartouche
\<^path> argument: cartouche
\<^path_binding> argument: cartouche
\<^plugin> argument: cartouche
\<^print>
\<^prop> argument: cartouche
\<^bash_function> argument: cartouche
\<^scala> argument: cartouche
\<^scala_function> argument: cartouche
\<^scala_method> argument: cartouche
\<^scala_object> argument: cartouche
\<^scala_thread> argument: cartouche
\<^scala_type> argument: cartouche
\<^session> argument: cartouche
\<^simproc> argument: cartouche
\<^sort> argument: cartouche
\<^syntax_const> argument: cartouche
\<^system_option> argument: cartouche
\<^term> argument: cartouche
\<^theory> argument: cartouche
\<^theory_context> argument: cartouche
\<^tool> argument: cartouche
\<^typ> argument: cartouche
\<^type_abbrev> argument: cartouche
\<^type_name> argument: cartouche
\<^type_syntax> argument: cartouche
\<^oracle_name> argument: cartouche
\<^code> argument: cartouche
\<^computation> argument: cartouche
\<^computation_conv> argument: cartouche
\<^computation_check> argument: cartouche