# Metadata
Metadata is data describing other data or activity: identifiers, endpoints, time, duration, routing, device, account, location, format, or transaction context. The exact fields and legal treatment depend on the system and authority.
## Notebook evidence
[[Scanned_20260730-1830]], PDF pages 6–7, approaches metadata through [[Call Detail Records]], automatic number identification, [[Pen Register|pen registers]], and [[Trap and Trace Device|trap-and-trace]] concepts. Page 4 separately maps network-level collection.
## Analytical significance
“Not content” does not mean “not revealing.” Aggregated metadata can expose relationships, routines, institutions, movement, and changes over time. Conversely, the word metadata should not be used as a catch-all: a carrier CDR, real-time signaling record, network flow, account log, and repository query log are different artifacts.
## Boundary
The existence of a metadata-capable system does not prove that a particular record was collected, retained, joined, queried, or used.
## Source
- [[Scanned_20260730-1830]], PDF pages 4 and 6–7.