line 1 column 1 - Warning: missing <!DOCTYPE> declaration
line 3 column 1 - Warning: <foo> is not approved by W3C
line 3 column 10 - Warning: <bar> is not approved by W3C
line 3 column 32 - Warning: <zippo> is not approved by W3C
line 5 column 1 - Warning: <zippo> is not approved by W3C
line 6 column 1 - Warning: <baz> is not approved by W3C
Info: Document content looks like HTML5
Tidy found 6 warnings and 0 errors!

About HTML Tidy: https://github.com/htacg/tidy-html5
Bug reports and comments: https://github.com/htacg/tidy-html5/issues
Official mailing list: https://lists.w3.org/Archives/Public/public-htacg/
Latest HTML specification: https://html.spec.whatwg.org/multipage/
Validate your HTML documents: https://validator.w3.org/nu/
Lobby your company to join the W3C: https://www.w3.org/Consortium

Do you speak a language other than English, or a different variant of 
English? Consider helping us to localize HTML Tidy. For details please see 
https://github.com/htacg/tidy-html5/blob/master/README/LOCALIZE.md
