Validator swears at XFN markup in HTML5?

Question

HTML

The authors of XFN specs did not answer - what to do with the fact that the W3C Validator began to swear at XFN markup in HTML5. Colleagues, I ask for your help.
1) Because HTML5 does not allow the profile attribute to be written in the head, we used this notation: />Now it is considered erroneous: Bad value profile for attribute rel on element link: Keyword profile is not registered.
2) Specifying XFN values ​​in the rel attribute of links now also causes an error: Bad value friend for attribute rel on element a: Keyword friend is not registered.

Answer 1

microformats.org/wiki/existing-rel-values#HTML5_link_type_extensions here you need to register the link type extension. And if they register, they will not swear.
Same for meta attributes - wiki.whatwg.org/wiki/MetaExtensions
Recent changes, so not many registered yet.