On Wednesday we attempted adding rel="noopener" to our links rendered in Chrome. Our understanding was that this would not affect referrers, and would simply prevent the new window from having window.opener set. We got reports, however, that referrers weren't being sent in Chrome - and were able to reproduce this behaviour.
One point of note, is that in Chrome we couple this with using meta referrer. This is usually set to "origin-when-cross-origin", but is switched to "origin" when an external link is clicked. We wondered whether perhaps there was a bug that appeared when meta referrer was used in our way alongside noopener.
Comment 1 by kinuko@chromium.org
, Jun 9 2016