See your exchanges, queues and bindings as a diagram, with the dead-letter paths drawn in: which queue dead-letters into which exchange, where alternate exchanges catch unroutable messages, and where a dead-letter exchange is missing or loops back. Paste a definitions export; nothing leaves your browser.
It runs in your browser; nothing is sent anywhere. Users, password hashes and permissions in the file are ignored. The export stays in this browser tab, so the other three tools pick it up without pasting it again.
Reading the diagram
Exchanges are on the left, queues on the right; a solid arrow is a binding, labelled with its routing key or headers.
Dashed amber: where a queue sends its dead letters (from x-dead-letter-exchange or the policy that applies). Dashed teal: an alternate exchange.
Red: a dead-letter exchange that does not exist, or dead letters that route back into the queue they came from.
Dashed outline: a queue no binding feeds; only the default exchange reaches it, by its name.
The default exchange is left out, because it is bound to every queue. Use the routing tester to follow a single message, and the upgrade check for the full list of findings.