Research of a Lifetime
The quest is unlocked after completing The Future of Hyrule scenario.
"A traveler you met on your way back from training is thoroughly absorbed by his research. Give him the materials he needs, then he'll give you what he picked up during his travels."
"The traveler said he's researching a subject that's a once-in-a-lifetime opportunity, and he hopes to elevate people's lives with his work. He will trade you for materials he finds useful."