Description of `mail-extract-address-components' says
 "extract full name and canonical address"
But it actually returns modified (canonicalized) full name like:

 (mail-extract-address-components "\"Nakayama, Y\" <yoichi@geiin.org>")
 => ("Y. Nakayama" "yoichi@geiin.org")
 (mail-extract-address-components "Y Nakayama <yoichi@geiin.org>")
 => ("Y. Nakayama" "yoichi@geiin.org")

So the description would be "extract canonical full name...".

By the way, I think it would be better that canonicalization of full
name is done outside and the extracting function just return full name
as it is.  It is because full-name canonicalization code strongly
depends on language, culture and custom to describe names(*1), and
dividing those two features will allow more general use of
`mail-extract-address-components'.

(*1) An example can be found at the next part of this message.
Picture version with note is at http://yoichi.geiin.org/tmp/mail-extr.png

Best regards,
-- 
Yoichi NAKAYAMA