Back in Chrome 54, Google introduced changes to the way pages are reloaded. The change was partially thanks to Facebook, who has been working with various browser vendors to improve browser caching. While the change isn't brand new, Google and Facebook are eager to share how well it has been working.
When you refresh a page, the browser checks the server to see if a given resource (web pages, images, scripts, etc) is still valid, in a process fittingly called revalidation.
was written by the awesome team at Android Police.