I've just followed this on my fresh Excalibur install, and fastfetch doesn't seem to be showing anything different to "X11" despite etrminal during installation confirming X11 getting uninstalled and replaced by Xlibre.
I used : ~$ env | grep -E -i 'x11|xorg|wayland'
XDG_SESSION_TYPE=x11
And that is what it shows me, am I missing something?