AFAIK even though (someone possibly correct me) libinput started as part of Weston it is now a separate and very successful input handling library that can be even used with the xserver (so Fedora uses it to handle all input on both X and wayland since F22 ). But I'm not sure what the situation is with libinput on Sailfish OS (IIRC Sailfish OS predates libinput and uses some custom code as a result) and if would be needed for GTK3 or other toolkits to work.