@Internal
    public boolean verifyInternal(final String domain) {
        final DomainRootInfo domainRootInfo = resolveDomainRoot(domain, null);
        if (domainRootInfo == null) {
            return false;
        }
        return domainRootInfo.root != null ||
                domainRootInfo.domainType == DomainType.PRIVATE && domainRootInfo.matchingKey != null;
    }
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