open any hyperlinks with a noopener attribute
Why use noopener?
When you open another page using target="_blank", the other page may run on the
same process as your page, unless Site Isolation is enabled. If the other page
Performance Benefits of rel=noopener.
The other page can access your window object with the window.opener property.
This exposes an attack surface because the other page can potentially redirect
your page to a malicious URL. See About rel=noopener.
Add rel="noopener" or rel="noreferrer" to each of the links that Lighthouse has
identified in your report. In general, when you use target="_blank", always add
rel="noopener" or rel="noreferrer".
-- Google Developers
The most obvious effect is that the page loads much faster than that the
"noopener" is absent.
Bug report & contribution