Dark data is the information companies collect but rarely use—often 60% to 80%...

https://xeon-wiki.win/index.php/What_Is_%E2%80%9COrphaned_Data%E2%80%9D_and_How_Do_I_Find_It%3F

Dark data is the information companies collect but rarely use—often 60% to 80% of stored files. This inactive data eats up storage costs, creates security risks, and clutters AI projects with irrelevant noise