...we're talking something like a carmine beetle, size-wise.
1. Right click a view and chose "Customize view"
2. In the "View as" menu chose "Categories"
3. In the settings to the right chose "Display an alphabet"
4. Then go back to the "view as" menu and switch to "File List".
The alphabet is still shown - as I understand it that feature is supposed to be limited to "Categories", or there would have been an option to turn it off in the "File List" settings. Either there should be (so one doesn't have to switch back to "categories" in order to disable it), or it should simply disable itself automatically when switching away from "Categories".