public boolean verify(final String domain) {
         if (domain == null) {
             return false;
         }
         return verifyInternal(domain.startsWith(".") ? domain.substring(1) : domain);
     }
Verifies if the given domain does not represent a public domain root and is
allowed to set cookies, have an identity represented by a certificate, etc.
<p>
This method tolerates a leading dot in the domain name, for example '.example.com'
which will be automatically stripped.
</p>

@since 5.5
httpclient5/src/main/java/org/apache/hc/client5/http/psl/PublicSuffixMatcher.java