Did my ships stream arrive?
If you point an AIS decoder at us, the first thing you want to know is whether anything landed. Until today the water side of the network had no way to tell you. The aircraft side has had one since August: a button on the feeder page that says whether a stream from your address is arriving, and whether it is credited to a station. Ships had nothing.
That gap was worst exactly where it mattered most. The UDP door on port 10110 takes plain NMEA sentences from any decoder, and it accepts anonymous senders on purpose, because asking someone to open an account before they can help is a good way to lose the two minutes of goodwill you had. An anonymous sender has no account page, no station, no statistics. There was no surface anywhere that could confirm their datagrams arrive, decode and count.
The check
/ais now carries a button that looks at your address and answers in one of seven ways. Your receiver is feeding and it is yours. Something at your address is feeding under a station id, and we won't say whose, because that id is what lets anyone feed under that name. Sentences are arriving anonymously and decoding fine. Datagrams are arriving and nothing decodes, which usually means a bad checksum or a decoder sending something other than AIVDM. Nothing is arriving. We could not compare at all.
The last one is there for a specific case. A browser on IPv6 next to a decoder on IPv4 is an ordinary home setup, and the two addresses cannot be compared. Answering "no" there would send somebody up a ladder to fix hardware that works. So the check says it could not check, and it says it in those words.
Your address is compared in memory and stored nowhere. A matching address proves nothing about ownership either, given shared office lines and carrier NAT, so the check attaches nothing to anybody. It answers about an address.
The ingest talks back
The other half is the reply to a delivery. POST /api/ais/feed used to answer with the count it accepted, which is true and says nothing about whether the traffic reached your station. It now includes your own numbers for the day: messages, distinct hulls, how many coverage squares you have lit, and whether today is your first day. Only your station. Nothing about anyone else's.
Before this, a volunteer who pasted the connector line waited a minute for the daily row to be written and another twenty seconds for the stations page to poll it. Now the answer comes back in the response to the post itself. If the summary fails to compute, the delivery still succeeds and the field is simply absent, because an accepted stream must never depend on a read.