One of the 121 Has No Address
Written later and filed to this date, as part of filling in every day of the year.
121 pages come out of a build of this site, and the gate that runs next counts 120. The missing one is the 404 page. It is the fallback document rather than a route anyone navigates to, so it has no URL to retire or redirect, and the gate exists to notice routes that disappear.
The gate is a committed list of the routes the last approved production build served. After every build the list is regenerated, and a route present in the previous build and absent from this one must be covered by one of exactly two things: an entry in the retirement registry, which means gone on purpose, answer 410; or a redirect rule, which means moved, send them to the new home. Anything else fails the build before it deploys. Deleting a page is fine. Deleting it silently is not.
It was written for a case that had already happened. A project page was removed, and the content file simply stopped existing, which is what deleting a page looks like from inside the repository: a diff like any other, with no consequence visible until someone requests the old URL. An outside reviewer did, weeks later, and got a full page with a “live” badge pointing at a dead host. The edge had cached the old response a week at a time, and later deploys did nothing to dislodge it, because nothing was answering at that path for them to replace. What finally removed the page was registering the route: a small function in front of the static files that answers 410 and forbids caching, which shadows whatever the edge is holding. A purge had been authorised. It turned out to be unnecessary.
The registry fixes a retirement someone registers. The manifest is for the one nobody does, and it is strictly stronger than finding the still unexplained week-long cache, because it stops the bad state being created rather than shortening how long it lasts. The registry has three entries. The redirects file has nine rules. The manifest has 120 lines and grows by one on most days, when a piece is published, which is the direction the gate does not mind.
The 121st page is the one you reach when a URL never existed, and the gate’s whole job is to keep every URL that once did from landing there.