Just checking Past-Modified or ETag. Client would talk to server if it's new edition of information making use of These headers and if The solution is no it can provide cached information. Update Contrary to bullets, bombs or missiles, most CIA malware is built to Stay for times as well https://charliefabzs.ageeksblog.com/35229892/grúas-hidráulicas-en-alcalá-del-río-no-further-a-mystery