I can't add Gmail as a mail account to Apple Mail in 10.14.6

You’re right: https://macdailynews.com/2019/09/24/apple-releases-safari-13-0-1/. Thank you.

Just an update on this issue. I installed the Safari update and unfortunately I am getting the same result. When I click on Google to add an account in Internet Accounts I get a message that Google requires authentication via Safari. (This is one of the strangest items I've run into--why would Google care what browser I use.) Anyway I click on OK to open Safari and absolutely nothing happens. I tried it with Safari open and closed and the result is the same. I have set up Gmail on another client. I imagine they will fix this someday. Very odd.

Thanks for your response. I believe you might be referring to the IOS 13.1 update. I don't see any Safari update for Mac.

Of course you were right. I thought about a restart but I assumed that they would tell me if a restart was required. Of course that was wrong. Thanks again. I'm all set now.