KPMG BACKGROUND CHECK

I was wondering if anyone knew how KPMG’s background check works?  The reason I ask is that they have asked me to fill out their online employment form, however, nowhere in the questionnaire does it ask me for phone numbers or email addresses of my previous employers.   My only concern is that many of the companies on my resume have been acquired by other firms, so how would KPMG be able to verify my prior employment without me providing contact info?