x-toolkit-scroll-bars

x-toolkit-scroll-bars is a variable defined in `C source code'.
Its value is

gtk

Documentation:
Which toolkit scroll bars Emacs uses, if any.
A value of nil means Emacs doesn't use toolkit scroll bars.
With the X Window system, the value is a symbol describing the
X toolkit. Possible values are: gtk, motif, xaw, or xaw3d.
With MS Windows or Nextstep, the value is t.