importers.explain

Dry-run the importer dispatch gates for one path without importing. Reports whether the file exists and reads, which importers claim it, and the verdict — would-import, or blocked with the exact gate (missing, unreadable, no-claimant, already-in-own-bundle, unchanged-content). The answer to "I wrote this file and nothing happened". The gates describe the write-triggered dispatch; importers.run forces through the already-in-own-bundle and unchanged-content gates, so a source blocked here can still be re-imported explicitly.