Postal references downloaded 5 October 2026. GeoNames CA and CA_full: https://download.geonames.org/export/zip/ ; attribution https://www.geonames.org/ . Source licence: Creative Commons Attribution, see source readme. Contains all well-formed matching Ontario records in the downloaded source; no assertion of completeness or current assignment in the Canada Post registry. FSA existence cross-check: Canada Post fsa-list-may-2025.pdf and Toronto Forward Sortation Area public map layer. Postal localities and three-character prefixes are not exact municipal boundaries. Full codes were matched by documented postal locality aliases; no synthetic codes were generated. Verify a specific address with Canada Post.