Visual primitive

Source note `has_source_note`

Attribution to the underlying data ("Source: …").

In serious editorial work this is non-negotiable. A source note signals "we did our work" and gives the reader a way to verify or find more. The best source notes also include the date the data was pulled.

When critical

Always — except for purely illustrative / schematic charts that explicitly say "Illustrative".

When optional

Schematic charts disclosed as illustrative.

Failures when missing

unsourced-data (reader cannot verify, suggests sloppiness)

Failures when present (badly)

Source note too small to read
Source note vague ("internal analysis") without methodology

Critical for families

Aspose property bindings

Title (often re-used as source note)