https://lists.whatwg.org/pipermail/whatwg-whatwg.org/2009-July/062981.html
[whatwg] Question on (new) header and hgroup
new headerwhatwgquestionhgroup
https://web-platform-dx.github.io/web-features-explorer/features/hgroup/
Web platform features explorer - hgroup
web platformfeaturesexplorerhgroup
https://caniuse.com/wf-hgroup
hgroup | Can I use... Support tables for HTML5, CSS3, etc
"Can I use" provides up-to-date browser support tables for support of front-end web technologies on desktop and mobile web browsers.
can i usesupport tableshgroupetc