What happens when you write a hyperlink to an external address with the nopener and noreferer
<a href="http://somewebsite.com" rel="nopener noreferer" target="_blank"/>
The target "_blank" instructs the browser to open the new URL in a new window or a new tab.
Doing so, sets the Window.opener object to the source window, thus allowing the JavaScript of the target window to do some manipulations.
When the "nopener" is used - this property is set to null.
The "noreferer" removes the Referer HTTP header, so the for the target website it seems as if the user clicked directly on the link (e.g. by typing it in the address bar).