Technology and tools
What is Metadata?
Information a file carries about itself rather than in its contents: when it was made, on what device, and sometimes where.
Metadata is information a file or message carries about itself rather than in its visible content: author name, creation and edit times, software version, device model, GPS coordinates, email routing headers.
It is often more revealing than the content. People scrub what they can see and forget what they cannot, so document properties, image EXIF data and mail headers regularly expose who made something, on what machine and when.