From my understanding this is the next iteration of OpenX4 E-Paper Community SDK - an sdk made by some of the core contributors of CrossPoint that abstracts the hardware of eink devices.

Huge props to the devs, that haven't just embraced people forking their repo - but have actually put in a lot effort to make it easier for anyone that wants to develop on these platforms.

It reads to me like FreeInk is the e-book reader and e-Paper SDK, and CrossPoint is the firmware that uses FreeInk.

I currently use CrossPoint, so I wanted to install this, but when I clicked the GitHub button, it just linked to the CrossPoint Firmware.