Dark data is the forgotten files and info sitting unused on your servers....

https://ricardosinterestingwords.swiftnestly.com/posts/is-it-true-that-unused-enterprise-data-grows-at-20-cagr-through-2027

Dark data is the forgotten files and info sitting unused on your servers. Around 55% of enterprise data goes dark, costing companies up to $2.5 million a year in wasted storage and management