Enabling two-finger swipe gesture for history navigation in Vivaldi on Linux

Using a two-finger swipe on the trackpad to move forward/back in history was not working for me, despite the option being enabled in the Vivaldi settings. I found the answer in this Vivaldi forum post:

Create a file ~/.var/app/com.vivaldi.Vivaldi/config/vivaldi-flags.conf and put that line

--enable-features=TouchpadOverscrollHistoryNavigation

into it.
Restart Vivaldi.

Now it works!