--- a/lib/texinputs/isabelle.sty Wed Nov 24 15:33:43 2021 +0100
+++ b/lib/texinputs/isabelle.sty Wed Nov 24 21:04:39 2021 +0100
@@ -275,29 +275,8 @@
\newcommand{\isamarkupcancel}[1]{\isa{\xout{#1}}}
-% tagged regions
-
-%plain TeX version of comment package -- much faster!
-\let\isafmtname\fmtname\def\fmtname{plain}
-\usepackage{comment}
-\let\fmtname\isafmtname
+% tags
\newcommand{\isafold}[1]{\emph{$\langle\mathord{\mathit{#1}}\rangle$}}
-\newcommand{\isakeeptag}[1]%
-{\includecomment{isadelim#1}\includecomment{isatag#1}\csarg\def{isafold#1}{}}
-\newcommand{\isadroptag}[1]%
-{\excludecomment{isadelim#1}\excludecomment{isatag#1}\csarg\def{isafold#1}{}}
-\newcommand{\isafoldtag}[1]%
-{\includecomment{isadelim#1}\excludecomment{isatag#1}\csarg\def{isafold#1}{\isafold{#1}}}
-
-\isakeeptag{document}
-\isakeeptag{theory}
-\isakeeptag{proof}
-\isakeeptag{ML}
-\isakeeptag{visible}
-\isadroptag{invisible}
-\isakeeptag{important}
-\isakeeptag{unimportant}
-
\IfFileExists{isabelletags.sty}{\usepackage{isabelletags}}{}