The typical method of changing trackpad behavior is to edit
/etc/X11/xorg.conf.d/<some number>-synaptics.conf. I'm running Fedora 25 running GNOME 3.22 and which uses Wayland by default, not X, so there is no
<some number>-synaptics.conf file in there, just this:
$ ls /etc/X11/xorg.conf.d/
So how do you change the trackpad behavior in this situation?