I have yahoo account with 3894 contacts, around 3500 of it were imported from Facebook.
Now, using a yahoo app project that connects to the API via oAuth to get the contacts, the result does not include Facebook contacts.
Exporting the contacts via Yahoo mail UI also does not include Facebook contacts, but this case is explained here (https://help.yahoo.com/kb/index?page=content&id=SLN22580&actp=search&viewlocale=en_US&searchid=1392159004276&locale=en_US&y=)
Can someone confirm that "Yahoo Contacts API result does not include Facebook contacts" is a bug or is intended by design? Is this documented somewhere?