High Quality Content by WIKIPEDIA articles! GtkHTML is a layout engine written in C using the GTK+ widget toolkit. It is primarily used by Novell Evolution and other GTK+ applications. The Balsa email client used GtkHTML as its layout engine for displaying emails until recently. In the long run, GtkHTML is planned to be phased out in favor of WebKit in GNOME.It was forked from KHTML by Larry Ewing with help from the late Ettore Perazzoli, and was published by Ximian before the company was bought by Novell. However, the GNOME project has devoted much more resources to the use of other open source layout engines, such as Gecko and WebKit, in GNOME applications such as Epiphany.