I study this interessing project since it make several parts of my utopic open-source calculator...
However congratulations to the proud french teachers that not only manage to launch this ambitious project, but also publish the specs, the PCB diagrams and a prototype of software.
I like the fact the Maxima will be the main CAS Engine, but also they manage to choose a tiny display driver framework that even I fail to notice
(I knew that a full X11 server would be overkill, so I try to search the viability of Wayland but also had the same problem
).
In fact, they choose the DirectFB and SDL combo to enable a basic graphic stack that would be nice to a low power machine, but also ease the portability of several homebrew and major programs.
Once I get some time (due to my PhD thesis), I will try build my own LibreCalc software once they publish the remaining main programs.