Safari 7 on my laptop supports the following tag:
<meta name="referrer" content="origin">
Answers to a previous question document support for various other browsers: "Why isn't the Referral Removed for Google HTTPS -> HTTP"?
Did Safari 6 support this? Based another article from the web, it looks like Safari 5 did not.
Safari 5: http://smerity.com/articles/2013/where_did_all_the_http_referrers_go.html
Answering my own question: at the latest, IOS/Safari 7. Unclear if this was in Safari 6 or not. http://searchengineland.com/rejoice-safari-is-once-again-providing-google-referral-information-in-ios-168493
FWIW, if anyone else is looking here, it's now in Firefox 38+: https://bugzilla.mozilla.org/show_bug.cgi?id=704320
Per direct contacts, it's included in IE11 and Chrome 25+ (including mobile, earlier on desktop).
