\input regression-test.tex
\DocumentMetadata{}
\documentclass{ltx-talk}
\NewDocumentCommand\lecture{O{}mm}{\TYPE{LECTURE KEPT}}
\usepackage[ignorenonframetext]{osglecture-modes-ltxtalk}
\ExplSyntaxOn
\cs_new_protected:Npn \test_keep_end:
  { \END \osglecture_modes_scan: }
\osglecture_modes_declare_allowed_command:nn { END } { test_keep_end: }
\ExplSyntaxOff
\begin{document}
\START
\lecture{Introduction}{intro}
\foobar
\begin{frame}
  \TYPE{FRAME KEPT}
\end{frame}
\END
\end{document}