You collected Kuro's Feather! To use this item, press A (Space) and then RT (Shift)! Kuro's Feather will allow Ori to glide freely or ride a wind current!
Kuro's Feather is the 6th skill that Ori learns. It allows them to fall very slowly while also being able to glide. It also will lift Ori up if they are inside of a Wind Tunnel. Ori gains this after successfully distracting Kuro who is blocking the path to the Misty Woods.
Hold Shift (RT/R2 on consoles) while midair to glide using Kuro's Feather.