...which will replace the diagnostic messages with this:

The markup is coloured thanks to Google's code prettifier . Also, note that clicking on a link will run RED against it, replacing the old "show links" function.

This is especially useful when, for example, you want to check to see if a site treats a specific browser differently, according to the User-Agent header.

When adding headers, keep in mind that RED isn't just a simple HTTP client; it actively probes resources using multiple requests with headers like Accept-Encoding, If-Modified-Since and If-None-Match to see how it will behave. If you try to set any of these headers, RED will warn you.

RED also has changed how it shows you the details of a specific message or header; if you mouse over one, you'll see a bubble like this appear:

The fine details are still being tweaked, so please be patient if you see some bugs here (and, of course, feel free to report them!).

Lots more is coming down the pipeline, stay tuned.