When you find and complete Challenges, a certain amount of Unepic Credits are available for you to use, even if you use a different character.

This implies Challenge data is saved outside of your character saves.

Where is the Challenge data saved?

I get a new computer every few years and Unepic saves are NOT saved on the Galaxy cloud atm, and while some people may find the Challenges fun, I find them to be a little tedious and restrictive and would prefer to keep the benefits I've already earned for future playthroughs. Meaning, I want to backup the completed Challenges data for future computers.

Thanks.

From the page linked here: retos.bin contains Challenge progress for the DRM-free versions.

Thanks for the answer! :D

(I also tested by moving the file out of the folder and it indeed cleared challenge data, then after moving it back in, I have my old challenge data again.)