in src/main/java/org/apache/sling/auth/saml2/impl/AuthenticationHandlerSAML2Impl.java [388:399]
AuthnRequest buildAuthnRequest() {
AuthnRequest authnRequest = Helpers.buildSAMLObject(AuthnRequest.class);
authnRequest.setIssueInstant(Instant.now());
authnRequest.setDestination(this.getSaml2IDPDestination());
authnRequest.setProtocolBinding(SAMLConstants.SAML2_POST_BINDING_URI);
// Entity ID
authnRequest.setAssertionConsumerServiceURL(this.getACSURL());
authnRequest.setID(Helpers.generateSecureRandomId());
authnRequest.setIssuer(buildIssuer());
authnRequest.setNameIDPolicy(buildNameIdPolicy());
return authnRequest;
}