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. However, the browser often forces revalidation on all sub-resources when refreshing, causing both the end-user and server to waste time and network usage for no reason.
Chrome was found to re-validate resources the most, so Facebook worked with them to try and fix this behavior. To make a long (but interesting) story short, both Chrome and Firefox had some odd behavior in place that was fixed. Now when Chrome refreshes a page, it typically only revalidates the main resource (the page itself, not the included images/scripts/etc).
The results speak for themselves - Facebook reports up to 28% faster reloads and 60% less validation requests, resulting in less data, battery, and CPU usage for a user's device. So next time you complain about Facebook, remember that they helped make refreshing in Chrome (and Firefox) a little faster.