It uses a "remote controlled browser to create screenshots with extended logging of user actions and data transfer to create a timestamped and digitally signed document to give a very reliable proof of the website contents while allowing to selectively exclude sensitive information and transparently decoding ssl (https) sessions".
Would the generated files hold up in court? No idea. I am not a lawyer (thank heavens), this is not legal advice, etc, etc. It may be prudent to have an actual notary (or twelve) verify and notarize instead (after conferring with a phalanx of attorneys, of course).
Related:
/misc | Aug 16, 2017