When the "Developer Tools" console is open in Google Chrome, the reload button gets a drop down menu with some options which are quite useful when developing web applications:
- Normal Reload: just reload the page, same as F5
- Hard reload: reload the page, but do not use anything from the cache for this request
- Empty Cache and Hard Reload: Empty the cache and reload (which is implicitly a hard reload then, since the cache is empty)
To actually open the menu, it is necessary to press and hold the reload button a short time, similar to the "back" button where chrome displays a page history then.
Also, the functionality is only available when at the same time the developer console is open for the specific page - the developer console can be opened by pressing F12.
See also What's the difference between “Normal Reload”, “Hard Reload”, and “Empty Cache and Hard Reload” in chrome? for some additional information.