X_DOC_CONFIG_KEY_UNKNOWN
Means
a page tells a reader to set a key AppConfig does not declare
Typical cause
only x <command> citations were resolved, so a fix: naming a deleted config key passed every gate — jobs.driver was cited four times in docs/ after 5.0.0 removed it, and two more pages cited pwa.backgroundSync.retry.maxAttempts (the field is a boolean) and realtime.url (it is urlEnv). A phrase-anchored negation filter keeps pages that correctly record a deletion out of the count
Fix
name a key AppConfig declares — bun run scripts/config-readers.ts --json lists every leaf