Worn File (removed)
A Worn File can be used in Forgotten Artificing tasks that require a File as an asset. They can also be used in Rare tasks as Optional assets that allow for Tools, where they give +8% Quality (increase chances for a higher tiered result).
Easiest spot, and free as well, is inside the workshop. Look at the Artisan counter with Fenella to the left... there is a small pile of wooden crates/ boxes to the right. It will say: Press (A) to look through the worn toolbox. They can be bought from M'tari Prin'tal in Protector's Enclave. They can also be traded and bought/sold on the Tarmalune Auction House.