The new project is LibrePhone:
> Librephone is a new initiative by the FSF to bring full computing freedom to mobile computing environments. The LibrePhone Project is a partnership with Rob Savoye, a developer who has worked on free software (including the GNU toolchain) since the 1980.
I found very little info about it online. There is this github org:
which mirrors PostMarketOS: https://github.com/LibrePhone/pmOS, 'The Linux distribution for mobile devices and beyond…'