Dark data is the inactive or unused info lurking in your systems—like 60% to...

https://felixssuperperspective.brightsora.com/posts/how-do-i-build-a-dark-data-cleanup-plan-that-legal-will-approve

Dark data is the inactive or unused info lurking in your systems—like 60% to 80% of your stored files. It costs money to keep and can create risks if sensitive info goes unnoticed