Dark data is the inactive or unused information sitting untouched in your...

https://emilyscoolnews.urbanvellum.com/posts/what-is-garbage-in-garbage-out-for-ai-data-pipelines

Dark data is the inactive or unused information sitting untouched in your systems—often making up 60%-80% of your stored files. It matters because it wastes space, drives up costs, and creates noise that can confuse AI projects