$ headless-seo-check http://127.0.0.1:4313 -a --verbose --plain
--- stdout+stderr ---
headless-seo-check: checking http://127.0.0.1:4313 …
headless-seo-check: 4 URLs pointed at another host, checked on 127.0.0.1:4313 instead
headless-seo-check: 4 of 4 URLs selected, from http://127.0.0.1:4313/sitemap.xml
run	http://127.0.0.1:4313	http://127.0.0.1:4313/sitemap.xml	4	4
page	http://127.0.0.1:4313/	checked	200	unclear	309	2	0	0	-
finding	http://127.0.0.1:4313/	info	render-mode-unclear	rendering mode undetermined — the response headers say nothing about caching
detail	http://127.0.0.1:4313/	render-mode-unclear	checked twice, the second response said no more
finding	http://127.0.0.1:4313/	warn	canonical-missing	no canonical link in the served HTML
page	http://127.0.0.1:4313/static/	checked	200	unclear	309	2	0	0	-
finding	http://127.0.0.1:4313/static/	info	render-mode-unclear	rendering mode undetermined — the response headers say nothing about caching
detail	http://127.0.0.1:4313/static/	render-mode-unclear	checked twice, the second response said no more
finding	http://127.0.0.1:4313/static/	warn	canonical-missing	no canonical link in the served HTML
page	http://127.0.0.1:4313/shell/	checked	200	unclear	0	0	0	1	-
finding	http://127.0.0.1:4313/shell/	info	render-mode-unclear	rendering mode undetermined — the response headers say nothing about caching
detail	http://127.0.0.1:4313/shell/	render-mode-unclear	checked twice, the second response said no more
finding	http://127.0.0.1:4313/shell/	warn	canonical-missing	no canonical link in the served HTML
finding	http://127.0.0.1:4313/shell/	error	empty-server-html	the served HTML carries 0 words — Googlebot has to run JavaScript to see this page
detail	http://127.0.0.1:4313/shell/	empty-server-html	7 <script src> + 4 KB inline JS + an empty root container
finding	http://127.0.0.1:4313/shell/	warn	no-internal-links	no links to any other page on this host — the navigation is not in the served HTML
page	http://127.0.0.1:4313/gone/	http-error	404	-	-	-	0	1	-
finding	http://127.0.0.1:4313/gone/	error	sitemap-url-error	HTTP 404 — in your sitemap, but not on your site
summary	checked	3
summary	dynamic	0
summary	unclear	3
summary	noindex_header	0
summary	hreflang_drift	0
summary	hreflang_dead_target	0
summary	empty_html	1
summary	sitemap_errors	1
summary	unreachable	0
summary	blocking	2
summary	warnings	4
summary	interrupted	0
summary	exit_code	1
--- exit code: 1 ---