Web Performance Power Tool: HTTP Archive (HAR) by Ilya Grigorik.
From the post:
When it comes to analyzing page performance, the network waterfall tab of your favorite HTTP monitoring tool (e.g. Chrome Dev Tools, Firebug, Fiddler, etc) is arguably the single most useful power tool at our disposal. Now, wouldn’t it be nice if we could export the waterfall for better bug reports, performance monitoring, or later in-depth analysis?
Well, good news, that is precisely what the HTTP Archive (HAR) data format was created for. Even better, chances are, you favorite monitoring tool already knows how to speak in HAR, which opens up a lot of possibilities – let’s explore.
If you are tuning or developing a web interface, there is much here you will find helpful.
The gathering of information for later analysis, by other tools, was what interested me the most.