retries verifiedWritten by the Hub
The retries queue
Where notices about rescheduled attempts would be published — not configured on a stock node, and absent from ours.
In detail
Introduced in 5.15.0 to replace the removed rabbitmq-retry. Since the stock config does not set the key, no such queue exists on a fresh node, and intermediate attempts are therefore recorded only in the send log. Worth revisiting for Hub: configuring this key would put deferred attempts into the broker, where the collector already reads, instead of leaving them in a log file it has to tail. That is a concrete improvement to MailerQ telemetry, and it would need measuring first — the volume of retry notices on a busy node is not small.