$ gsettings get org.gnome.desktop.interface cursor-theme
No such schema “org.gnome.desktop.interface”

$ MOZ_ENABLE_WAYLAND=1 firefox
[...]
Gdk-Message: 15:15:20.123: Unable to load hand2 from the cursor theme
Gdk-Message: 15:15:20.300: Unable to load hand2 from the cursor theme
Gdk-Message: 15:15:20.536: Unable to load hand2 from the cursor theme
Gdk-Message: 15:15:52.250: Unable to load hand2 from the cursor theme
Gdk-Message: 15:15:52.350: Unable to load hand2 from the cursor theme
Gdk-Message: 15:15:52.834: Unable to load hand2 from the cursor theme
Gdk-Message: 15:15:52.933: Unable to load hand2 from the cursor theme

$ emacs -Q # --with-pgtk
Gdk-Message: 15:16:34.736: Unable to load sb_v_double_arrow from the cursor theme
Gdk-Message: 15:16:34.736: Unable to load sb_h_double_arrow from the cursor theme
Gdk-Message: 15:16:35.272: Unable to load hand2 from the cursor theme
Gdk-Message: 15:16:35.272: Unable to load sb_h_double_arrow from the cursor theme
Gdk-Message: 15:16:35.272: Unable to load sb_v_double_arrow from the cursor theme

$ truss emacs -Q 2>&1 | fgrep /cursor
[...]
open("/home/foo/.icons/default/cursors/",O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC,00) ERR#2 'No such file or directory'
open("/usr/share/icons/default/cursors/",O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC,00) ERR#2 'No such file or directory'
open("/usr/share/pixmaps/default/cursors/",O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC,00) ERR#2 'No such file or directory'
open("/home/foo/.cursors/default/cursors/",O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC,00) ERR#2 'No such file or directory'
open("/usr/share/cursors/xorg-x11/default/cursors/",O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC,00) ERR#2 'No such file or directory'
open("/usr/local/share/icons/default/cursors/",O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC,00) ERR#2 'No such file or directory'
[...]