Can anyone one tell me what this icon does and how to disable it please?
This icon denotes the Chiral Scrolling feature.
When enabled Chiral Scrolling allows users to scroll down a page by moving the finger vertically down the right side of the Touchpad, and scrolling can be continued by moving the finger to the bottom left in a circular motion.
It can be deactivated in Touchpad settings
Control Panel > Hardware and Sound > Mouse > Ultranav tab.