Credible

https://www.powerlineblog.com/archives/2020/10/how-do-we-know-the-hunter-joe-biden-documents-are-real.php

citing to

https://townhall.com/tipsheet/bethbaumann/2020/10/17/rudy-giuliani-reveals-how-he-verified-the-data-on-hunter-bidens-hard-drive-n2578284