With all respect to the younger generation, this is project is oversold compared to previous similar projects.

BTW, which OSHW project is advanced enough to deserve more contributions ?

Back to paxo one, According to

https://github.com/paxo-phone/paxo-electronic

It is integration of SIM800L modem with ESP32

Software side, the main app (aka OS):

https://github.com/paxo-phone/PaxOS-9