Google's John Mueller said in that video hangout at the 39:51 mark that Google does try to recognize "additional details about information about the author, information about the reviewers, about the website overall, through through a number of ways." This question was directly related to how Google understands content from medical and health sites.

He said:

We we do try to recognize kind of these additional details about information about the author, information about the reviewers, about the website overall, through through a number of ways. Partially through the content directly. So kind of similar to how users would see it, if they go to the page and they see kind of information about who has reviewed this content or who has provided it. That's really useful. If it's just like hidden away in structured data then that's not very useful for users because users tend not to use view source when looking at a page to determine whether or not they should trust it. So I would try to find an approach that works well primarily for users and focus on that.

This is similar to what we wrote when we covered that Google: YMYL Sites Should Have An Expert To Write The Content and Google Algorithms Detect & Adjust Rankings For YMYL Queries.

The question is how does Google go about doing this? John said "through through a number of ways." "Partially through the content directly," he added but also mentioned only structured data is probably not the best way to convey this information to Google in a trusted way.

Hat tip to Glenn Gabe:

Worried about E-A-T for a medical site? JM: Google does try to recognize additional details about the author, medical reviewers, about the site overall, through a # of ways (& partially through the content directly). So, similar to how users would see it: https://t.co/oK0jssHP0d pic.twitter.com/ubfhgQ0zF7 — Glenn Gabe (@glenngabe) August 12, 2019

Forum discussion at Twitter.

Update" Bit more from John on this now: