@Override
    public X509Certificate[] getCertificateChain(String alias) {
        return delegate.getCertificateChain(alias);
    }
{@link X509ExtendedKeyManager} chooses the given alias for the server side.
spring/boot3-autoconfigure/src/main/java/com/linecorp/armeria/internal/spring/CustomAliasX509ExtendedKeyManager.java