For universal ctags, there is a readtags command that can list all tags, but this works only for a lowercase tags file, which is in its native format. It doesn't work for uppercase TAGS file, which is in Emacs format.
For debugging purposes, is there any way to list all the tags in an Emacs formatted universal ctags file?
readtags -t TAGS -lper the man page - and this has nothing to do with Emacs.