# Source notice

The source tables in `raw/` were downloaded from the National Institute of Standards and Technology's CODATA fundamental-constants pages.

Each file's source URL, byte size, retrieval date, and SHA-256 hash are recorded in `source-manifest.json`.

The tracker adds only its own parsing, fixed constant-set definition, uncertainty calculations, aggregate series, validation checks, and public presentation. NIST and CODATA remain the authoritative sources for the underlying recommended values and uncertainties.