Within that list you will see an item labeled IconSpacing, that is the setting for horizontal distance between desktop icons. The item labeled IconVerticalSpacing is, obviously, for vertical distance.

Once you’ve installed it, you’ll see a new icon on the toolbar on the left, which looks like four horizontal lines on top of each other. Click on it to show or hide the vertical tab list.

Truth be told, one reason why I haven’t given up Edge’s vertical tabs may be because I use other browsers regularly, too, and they have the familiar spread of horizontal tabs.