Your browser saves a cache of most pages you visit. Wouldn't it be handy if you could access that cache when you lose your internet connection? By enabling the Offline Auto-Reload Mode flag, you can do just that.
As Android Police points out, this feature is available in all versions of desktop and Android Chrome, though it occasionally goes by the name Show Saved Copy. Once you turn it on, you'll see a "Show Saved Copy" button when Chrome can't load a page, but has a cached version available.
To turn it on, go to chrome://flags and search for either "Auto-Reload" or "Show Saved Copy" and select "Enabled" or "Enabled: Primary" from the drop down box, depending on what's available.