thead/tfoot/tbody were introduced in HTML 4, with tbody mandatory (that is, `table > tr` was now invalid), but implied (that is, its start and end tags were bot

thead/tfoot/tbody were introduced in HTML 4, with tbody mandatory (that is, `table > tr` was now invalid), but implied (that is, its start and end tags were both optional, so that <table><tr>…</tr></table> would be parsed the same as <table><tbody><tr>…</tr></tbody></table>). Source: https://www.w3.org/TR/html4/struct/tables.html#h-11.2 https://www.w3.org/TR/html4/struct/tables.html#h-11.2: <!ELEMENT TABLE - - (CAPTION?, (COL*|COLGROUP*), THEAD?, TFOOT?, TBODY+)> <!ELEMENT TBODY O O (TR)+ -- table body -->