Note gnus.general appears *twice* because `gnus-topic-change-level' on a
topicless group will blithely add it to gnus-topic-alist without updating the
group buffer to reflect its new position in the "topology."

emacs-27.1 -Q --batch \
--eval "(custom-set-variables \
 '(network-security-level (quote low)) \
 '(gnus-interactive-exit (quote quiet)) \
 '(gnus-large-newsgroup 4000) \
 '(gnus-select-method (quote (nntp \"news.gmane.io\"))) \
 '(gnus-add-timestamp-to-message (quote log)) \
 '(gnus-before-startup-hook (quote (toggle-debug-on-error))) \
 '(gnus-always-read-dribble-file t) \
 '(gnus-use-dribble-file nil) \
 '(gnus-read-newsrc-file nil) \
 '(gnus-parameters (quote ((\"^nntp\" (display . 1000))))) \
 '(gnus-summary-prepared-hook (quote (gnus-summary-hide-all-threads))) \
 '(gnus-startup-file \"/var/tmp/foo\") \
 )" \
-l gnus-topic \
--eval "(add-hook 'gnus-group-mode-hook 'gnus-topic-mode)" \
-f gnus \
--eval "(gnus-server-open-all-servers)" \
--eval "(gnus-fetch-group \"nntp+news.gmane.io:gmane.emacs.gnus.general\")" \
--eval "(with-current-buffer (gnus-summary-buffer-name \"nntp+news.gmane.io:gmane.emacs.gnus.general\") (gnus-summary-exit))" \
--eval "(goto-char (point-min))" \
--eval "(save-excursion (gnus-group-subscribe nil))" \
--eval "(gnus-topic-move-group nil \"misc\")" \
--eval "(princ (buffer-string) #'external-debugging-output)"