Never heard of the source. We need verification.
http://www.foxnews.com/tech/2016/06/21/after-dnc-attack-hacker-guccifer-2-0-releases-hillary-clinton-dossier.html
The repository of leaked docs from Guccifer 2.0 is here:
https://guccifer2.wordpress.com/2016/06/21/hillary-clinton/