Show WebP Thumbnails In GTK Applications (Nautilus, Thunar, Etc.) Using WebP GDK Pixbuf Loader Library

I was looking for a way to get WebP image thumbnails in GTK applications (especially Nautilus/GNOME Files), and most solutions I found were “hacky,” until I found the rather unknown WebP GDK Pixbuf Loader library. So I thought I’d write about it here on Linux Uprising, in case some of you are also interested in this.