Recently I made a mistake.
I began reading comments on a blog post.
I find it amazing watching all of the armchair quarterbacks commenting on what the reality is around this device.
First and foremost, Remarkable goes far further in the spirit of Free/Libre/Open Source Software than many (if not most) vendors do.
Anyone who has one of their devices, as I do, gets a lot of flexibility in using it, thanks to a thriving free software community built up around the device.
At the heart, it's running an Open Embedded built version of Linux. Remarkable is very active on GitHub, even releasing some of their backend engineering code.
The update model is the same as CoreOS' Container Linux (my alma mater, where I was involved with many aspects of our core engineering), which is to say using the Omaha Protocol to deliver payloads to the devices for automated updates. I was surprised to see they even used our fork of "update_engine" (the Omaha protocol client, of which our fork was taken from Chromium OS... which uses Gentoo as the SDK, as opposed to Open Embedded mentioned above).
Remarkable has also made it easy for folks around the binary firmware blobs that integrated circuit manufacturers require their customers to use, by putting them into relevant repos (brcmfmac-firmware).
Remarkable has been candid that the primary application they develop which is "proprietary" is Xochitl (the GUI component of the UI, think of it effectively as the window manager), but clear community supported documentation for developing other Qt based applications exists (remarkablewiki), and other folks have done deep dives into exploring aspects of how the hardware works, writing directly to the framebuffer, and so on (duckpond).
From the "running applications on the device" perspective both
I and others have written up documentation
on using the Entware package system (also used with QNAP, Synology, Android,
and other Linux devices) with the Remarkable device. Need jq? Immediately
compiled and available. How about you really (for some reason) want to run
NGINX on the device? Seconds after running opkg install nginx, you're on
your way.
Somewhere out there, a company selling a $400 e-paper notebook accidentally built the most hackable Linux appliance I own, and the comment section still wants to argue about whether it's "really" open.