I couldn’t find anyone else documenting this, so I figured someone else might someday benefit from knowing this.
As of today, this is the HTTP User-Agent string sent by the first (and so far, only) version of the Amazon Kindle.
Mozilla/4.0 (compatible; Linux 2.6.10) NetFront/3.3 Kindle/1.0 (screen 600x800)
It’s probably safe to detect it with a simple substring match:
And while the usage numbers aren’t there yet to justify a ton of effort, Kindle readers can strongly benefit from a few layout tweaks and optimizations.
Be careful of caching potential: as far as I can tell, Amazon is proxying the content.