The software is no longer available for desktop only. With a few commands, you can install and start a Plasma session on the phone screen with PureOS.
#install sudo tasksel install desktop kde-desktop sudo apt install plasma-wayland-protocols plasma-workspace-wayland kwin-wayland-backend-fbdev kde-standard #run sudo systemctl stop phosh export WAYLAND_DISPLAY = wayland-0 startplasma-wayland --framebuffer --fb-device / dev / fb0 & # or fb1 to select the screen you want it on plasmashell
or
#mate on PureOS 10 sudo apt install xinit xorg xterm x2x mate #run X11 sudo systemctl stop phosh sudo xinit - -masterfd 9 9 <> / dev / dri / card1 & export DISPLAY =: 0 mate-session
This new version of PureOS is already used on Librem Mini v2 and Librem 14 and will be available soon for Librem 5.