What a page opened in a new tab can reach

Each link opens a small report page. It says whether it can reach this tab, and what referrer it got.

Same tab (no target)
Replaces this page. Use the back button to return.
New tab (target="_blank")
Current browsers treat this as rel="noopener": the report finds no opener.
New tab with an opener (target="_blank" rel="opener")
Asks for the old behavior. The report can reach this tab, and could send it to another address.
New tab, no referrer (rel="noreferrer")
No opener and no Referer header: the report's document.referrer is empty.
A named tab (target="trail-help")
The first click opens a tab called trail-help. A second click loads into that same tab instead of opening another one.