$ npm install broken-link-checker -gRun it against production site.
$ rm -f links.log; npx blc https://runme.dev -ro > links.log
# expected to fail if any non 2xx/3xx status code occurAll 404s.
$ grep "HTTP_404" links.logIgnore externals.
$ cat links.log | grep -v "https://github.com" | grep -v "https://marketplace" | grep "HTTP_404"