This likely happened during the 3.16 cycle with the migration of touchpad
settings to org.gnome.desktop.peripherals from
org.gnome.settings-daemon.peripherals. It therefore likely affects Leap too,
but I don't actually have a way of testing that (Leap is on the computer with a
mouse, no touchpad). Anyway, as of TW 20151106:
----
> gsettings list-keys org.gnome.desktop.peripherals.touchpad
natural-scroll
click-method
scroll-method
left-handed
send-events
tap-to-click
speed
----

while our glib branding still specifies 
----
[org.gnome.settings-daemon.peripherals.touchpad]
## Enable tap-to-click by default (bnc#554884,fate#310811)
## http://lists.opensuse.org/opensuse-factory/2012-06/msg01087.html
tap-to-click = true
## In order to prevent accidental clicks due to tap-to-click,
## disable tap-to-click while typing
disable-while-typing = true
----
which no longer works.