I've also heard (but not verified) that kobo's firmware isn't locked down the way amazon's is, so you can compile and install your own apps and modify system scripts. In other words it's your device, not Amazon's.
The MobileRead forums are where most of the unofficial discussion/development happens: https://www.mobileread.com/forums/forumdisplay.php?f=223
That's good to hear. I have no problem with a device vendor focusing on just making sure their device works well, as long as they're not trying to close it off and actively working against external developers. I'd heard stuff like Kindle blows physical fuses so that one can't install older firmware and stuff like that so they actively prevent users from having control of their device. I have no desire to be a customer of such types of vendors.
[0]: https://www.amazon.com/Pocketbook-Touch-HD-Metallic-Grey/dp/...