public boolean isLoginFormUsernameInputVisible(final WebEngineContext vars) {
        val requestContext = RequestContextHolder.getRequestContext();
        val providers = webflowExecutionPlan.getWebflowLoginContextProviders();
        return requestContext != null
               && (WebUtils.isCasLoginFormViewable(requestContext) || providers.isEmpty()
                   || providers.stream().anyMatch(provider -> provider.isLoginFormUsernameInputVisible(requestContext)));
    }
Is login form username editable?.

@param vars the vars
@return true/false
support/cas-server-support-thymeleaf-core/src/main/java/org/apereo/cas/services/web/CasThymeleafTemplatesDirector.java