line 1 column 1 - Warning: missing <!DOCTYPE> declaration
line 12 column 7 - Warning: <center> isn't allowed in <tr> elements
line 11 column 5 - Info: <tr> previously mentioned
line 12 column 7 - Warning: missing </center> before <td>
line 8 column 3 - Info: missing optional end tag </dd>
line 10 column 5 - Warning: The summary attribute on the <table> element is obsolete in HTML5
line 12 column 7 - Warning: trimming empty <center>
line 3 column 1 - Warning: <frameset> element removed from HTML5
line 4 column 3 - Warning: <noframes> element removed from HTML5
Info: Document content looks like HTML5
Tidy found 7 warnings and 0 errors!

One or more empty elements were present in the source document but
dropped on output. If these elements are necessary or you don't want
this behavior, then consider setting the option "drop-empty-elements"
to no.

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