Dark data is all the information stored but never used—think of files taking up...

https://www.start-bookmarks.win/dark-data-is-the-hidden-information-your-company-collects-but-never-uses-like

Dark data is all the information stored but never used—think of files taking up space but adding no value. Around 55% of enterprise data falls into this category, which leads to wasted storage costs and higher security risks