The Goron Fabric is a key item from Tears of the Kingdom.
Tears of the Kingdom
"Tough fabric bearing a Goron design. It looks like it could be used to make a paraglider."
The Goron Fabric is a piece of red fabric with the Goron symbol, based on the Goron's Ruby, and various other streaks picked out in a neutral beige colour, and some streaks of brown. It can be applied to Link's paraglider by Sayge at the Kochi Dye Shop for 20 rupees.
It is obtained as a prize for completing Kabetta's Mine Cart course on Death Mountain in the Mine-Cart Land: Death Mountain Side Quest. This entails hitting eight of his targets without leaving the mine cart or taking more than two minutes to complete the course.