jquery/jquery-mobile — pull request #5327 by ErwanMAS (2012-11-24 09:47:52+00:00)
Title: collapsise  : abitilty to have no icon 

move default values from collapsedIcon / expandedIcon / iconPos in the "options"
section of the widget instead in the main code .

so we have the ability do not display a icon for collapsible ( with setting collapsedIcon to false )