@Override
    public Collection<CredentialRegistration> getRegistrationsByUsername(final String username) {
        val restProperties = getProperties().getAuthn().getMfa().getWebAuthn().getRest();
        HttpResponse response = null;
        try {
            val parameters = CollectionUtils.<String, String>wrap("username", username);
            val exec = HttpExecutionRequest.builder()
                .basicAuthPassword(restProperties.getBasicAuthPassword())
                .basicAuthUsername(restProperties.getBasicAuthUsername())
                .method(HttpMethod.GET)
                .url(restProperties.getUrl())
                .parameters(parameters)
                .headers(restProperties.getHeaders())
                .build();
            response = HttpUtils.execute(exec);
            if (Objects.requireNonNull(response).getCode() == HttpStatus.OK.value()) {
                try (val content = ((HttpEntityContainer) response).getEntity().getContent()) {
                    val result = getCipherExecutor().decode(IOUtils.toString(content, StandardCharsets.UTF_8));
                    return WebAuthnUtils.getObjectMapper().readValue(result, new TypeReference<List<CredentialRegistration>>() {
                    });
                }
            }
        } catch (final Exception e) {
            LoggingUtils.error(LOGGER, e);
        } finally {
            HttpUtils.close(response);
        }
        return new ArrayList<>();
    }
This is {@link RestfulWebAuthnCredentialRepository}.

@author Misagh Moayyed
@since 6.4.0
support/cas-server-support-webauthn-rest/src/main/java/org/apereo/cas/webauthn/RestfulWebAuthnCredentialRepository.java