It seems that there are missing files in the texinfo tarball file of GNU Bison.
After downloading and extracting <https://www.gnu.org/software/bison/manual/bison.texi.tar.gz>, I run the following command and get these errors: $ texi2any --epub3 bison.texi bison.texi:11548: warning: @anchor should not appear in @itemx bison.texi:11871: warning: @anchor should not appear in @itemx bison.texi:10854: warning: @image file `figs/example' (for HTML) not found, using `figs/example.svg' .texi2any-real: @image file `figs/example' can not be copied bison.texi:10892: warning: @image file `figs/example-shift' (for HTML) not found, using `figs/example-shift.svg' .texi2any-real: @image file `figs/example-shift' can not be copied bison.texi:10914: warning: @image file `figs/example-reduce' (for HTML) not found, using `figs/example-reduce.svg' .texi2any-real: @image file `figs/example-reduce' can not be copied The texi2any version (just for completeness): $ texi2any --version texi2any (GNU texinfo) 7.0.3 Copyright (C) 2023 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Many thanks, Yuval Langer.
