advise browser not to set referrerer for external links and open them in new tab

layouts/_default/_markup/render-link.html

@@ -0,0 +1,18 @@
+{{- $parsedTitle := dict -}}
+{{- with .Title -}}
+  {{- $parsedTitle = partial "functions/parse-title-attribute.html" . -}}
+{{- end -}}
+{{- $baseurl := urls.Parse .Page.Site.BaseURL -}}
+{{- $desturl := urls.Parse .Destination -}}
+
+<a href="{{ .Destination | safeURL }}"
+  {{- with $parsedTitle.title }} title="{{ . }}"{{- end -}}
+  {{- with $parsedTitle.attributes -}}
+    {{- range $k, $v := . -}}
+      {{- printf " %s=%q" $k $v | safeHTMLAttr -}}
+    {{- end -}}
+  {{- end -}}
+  {{- if and (strings.HasPrefix .Destination "http") (not (strings.HasPrefix $desturl.Host $baseurl.Host)) }} target="_blank" rel="external noreferrer noopener"{{ end -}}
+  >{{ .Text | safeHTML }}</a>
+
+{{- /* Strip trailing space. Code by djibe, thanks to jmooring & killbus */ -}}