rel="home" is shown as error bit it is in the Microformat wiki

Bad value home for attribute rel on element a: Keyword home is not
registered. 
.tp://www.toseco.at/" title="ToSeCo Consulting" rel="home">ToSeCo
Consulting</a>
Syntax of link type valid for <a> and <area>:
A whitespace-separated list of link types listed as allowed on <a> and
<area> in the
<http://www.whatwg.org/specs/web-apps/current-work/multipage/links.html#link
Types> HTML specification or listed as an allowed on <a> and <area> on the
<http://microformats.org/wiki/existing-rel-values#HTML5_link_type_extensions
> Microformats wiki without duplicate keywords in the list. You can register
link types on the
<http://microformats.org/wiki/existing-rel-values#HTML5_link_type_extensions
> Microformats wiki yourself. 
 
 
The full line is:
<a href="http://www.toseco.at/" title="ToSeCo Consulting" rel="home">ToSeCo
Consulting</a>
 
See:
http://microformats.org/wiki/existing-rel-values#HTML5_link_type_extensions
http://microformats.org/wiki/rel-home   it in in it 
NOTE: Whenever possible, give the address of the document you were checking.