There is currently no way to “unhide” / “show” the email address associated with a Member of a “Sharing with” list [File->Share… on a Mac].
I might have expected a list of email addresses for both pending and members, with the addition of the username once a pending becomes a member.
The need for this is strong when managing long lists, and/or circumstances where a given indiviual has and uses multiple email addresses / endnote accounts.
- rd