This is the average over all requests that day.

[kexej28769@nongnue]

This is technically not "downloading a page" but "receiving data in response to a URL request" - it's not based on rendering the page, it includes all requests made.
And that:


Because Google can take a very different set of austria number data while crawling your site, and because this graph doesn't account for anything with page rendering, it's not useful as a measure of your site's true performance.

For this reason, John pointed out that:

There is no point in focusing on this number with your eyes closed .
Which I completely agree with. The graph can be useful for identifying certain classes of backend issues, but there are probably better ways for you to do this (like WebPageTest.org , which I'm a big fan of).

Okay, so now that we understand this graph and what it represents, let's look at the next option: Google WRS.

Google Bot and Web Rendering Service
Google's WRS is their headless browser mechanism based on Chrome 41, used for things like "Fetch as Googlebot" in Search Console, and is the crawler that Googlebot is using when it crawls pages.