Dark data is the information your organization collects but never uses—about...

https://bravo-wiki.win/index.php/What_Are_Egress_Costs_and_Why_Do_They_Matter_for_Dark_Data%3F

Dark data is the information your organization collects but never uses—about 55% on average. This inactive data not only wastes storage and backup costs but also increases ransomware and breach risks