For one, unlike most Android devices, you don't have to root the RM. It comes with SSH running and you have the root password. The company's Github [1] has most of the source code, from their Linux kernel to the software update daemon.
Their CTO, Martin Sandsmark, is a long-time KDE developer.
Unfortunately, xochitl (the device's main UI) isn't open. It's a major miss in their open approach, and frankly I don't get why they would keep it closed - the RM's competitive advantage is in the hardware design, the xochitl software is merely okay and could only benefit from user patches.
Their CTO, Martin Sandsmark, is a long-time KDE developer.
Unfortunately, xochitl (the device's main UI) isn't open. It's a major miss in their open approach, and frankly I don't get why they would keep it closed - the RM's competitive advantage is in the hardware design, the xochitl software is merely okay and could only benefit from user patches.
[1] https://github.com/reMarkable