\directlua{unhook_expl()}
% See baseregisters for list of toks pdfvariables
\directlua{initialize_pdf_toks()}
% We hardcode the ids of two catcodetables. If they ever change in the format, abort.
\if 0\ifnum1=\catcodetable@initex\else\expandafter1\fi\ifnum2=\catcodetable@string\else\expandafter1\fi 0\else
  \errmessage{Inconsistent catcodetable identifiers}
\fi
\ifx\@tfor\undefined
  \def\@tfor#1\do#2{}
\fi
\input expl3.ltx