[jhowell]

I did a little more poking into this feature to see if I could find out anything else. Some of this is speculative. I don't have enough interest in this to spend much more time on it.

From what I can tell the enabling of the dark mode icon in the quick settings toolbar is a feature locked in the firmware, not subject to triggering after the fact.

It seems likely that the configuration for this option is stored in the file "/etc/deviceConfig.conf". This file is encrypted making it hard to tell what is in there. However there is a utility present in the Kindle firmware that might be able to decrypt it. I can provide more details if someone with a jailbroken device with shell access wants to try decoding this file.

There is the question of why only a very few people have reported having it. Perhaps is is only enabled in firmware targeted to a narrow set of devices or that specific firmware was only being delivered for a brief time. It would be useful if someone who actually has the feature enabled would report their exact Kindle model (serial number prefix) and firmware version including the build number.