At line 237 of taxonomy_block.module we have
$content .= '<div id=". $x .'" class="'. (substr(decbin($x), -1) ? 'flip' : 'flop') .'"> (etc)
but providing a numeric id (actually, an id starting with a number) is forbidden by XHTML standards and results in the page not validating (validator.w3.org):
Line 49, column 32: value of attribute "id" invalid: "1" cannot start a name
Comments
Comment #1
crunchywelch commentedfixed in cvs
Comment #2
crunchywelch commentedComment #3
(not verified) commented