via smashingmagazine.com => original post link
First of all, it would be remiss of me to give the Chrome browser all the credit here, when the other two main browsers (Safari and Firefox) have had this concept for quite some time now, though there are some subtle differences in all three implementations.
So, Chrome was playing catch-up here. However, as the world’s most popular browser and the only browser feeding back the Core Web Vitals information for any search ranking boasting, Chrome getting this (finally, some might say) is important. Plus, they’ve created some more transparency about this, both in documentation and tooling. Not to mention the many other Chromium-based browsers (e.g. Edge, Opera, Brave) will now also have gotten this functionality too.
With that caveat out of the way, let’s get to the guts of the article: What is the Back/Forward Cache and why does it matter so much? As its name implies, this is a special cache used to remember the web page as you browse away from that web page, so if you browse back to it later, it can load a lot quicker.