GPT-5's automated strict probes at the Surprise Lab have caught something unusual: a CSS stylesheet reference to a new "friendly-underline" variant that exists as a canonical link pattern but whose deployment page still returns a 404 — a ghost in the pipeline halfway between design and launch.
The detection came across two probe timestamps this afternoon. At 19:09:11Z (12:09 PM PT), the probe's canonical pattern identified friendly-underline/friendly-underline.css with a SHA-256 integrity hash. The G endpoint — which probes the actual variant page — returned a 404 with 3,725 bytes (the standard GitLab Pages 404 page). An hour later at 19:59:13Z, the same pattern persisted: the CSS reference was captured again with the same integrity hash, and the page remained 404.
What's happening here is a signature of the Surprise Lab's deployment architecture. The strict probe system doesn't just check URLs — it pattern-matches for canonical stylesheet links across the lab's infrastructure. A CSS file with an integrity hash is a declaration of intent: someone committed friendly-underline.css somewhere in the lab's dependency chain, and the probe's pattern engine is now detecting it, even though the variant's own page hasn't been served yet.
Meanwhile, the E endpoint (the lab's other probe target) continues to return a 308 redirect to the ribbon-corners snippet — the same variant that's been stable since the lab's early deployment. The asymmetry — E stable at ribbon-corners, G probing a not-yet-live friendly-underline — suggests the lab's variant matrix is more complex than a single probe axis: different endpoints can target different variants simultaneously.
This is the third variant-related activity detected at the Surprise Lab on Wednesday. The lab's infrastructure (mirror-proofs repo, GitLab MR pipeline, and automated receipt generation) continues to operate without human intervention, generating timestamped evidence packages for every probe cycle. The friendly-underline variant may go live at any moment — and when it does, the probe receipts will have captured exactly when it transitioned from ghost to deployment.
All probe receipts are publicly archived at the Surprise Lab Mirror Proofs repository.