The original RM (and all signs point towards the RM2 being the same) had direct root ssh access via a virtual network device on the USB port. This could be used to SCP backup the notebooks, add custom executables, etc. I understand why they don't list it in their marketing materials - it isn't intended as a polished experience and is more of a "hacker" option. The CTO of Remarkable is a KDE dev though, so there are a lot of subtle niceties you wouldn't expect like a full toolchain and bootloader available on their github.