Understand why Google can serve unindexed hreflang URLs and how unique local content gives market pages a reason to matter in search and AI answers.

In 2018, Glenn Gabe published one of the more puzzling SEO case studies of the decade. A client was canonicalizing UK and Indian hreflang URLs to a U.S. version, technically wrong, and against Google’s own guidance. Yet, the “wrong” URLs kept surfacing correctly in country-specific search results, even though Search Console showed them as not indexed. When Gabe asked John Mueller about it during a webmaster hangout, Mueller confirmed the behavior was real: Google could swap in the correct country/language URL at the SERP level, even when only one page in the hreflang cluster was actually indexed. It was treated as a curiosity, a “magic trick,” as Gabe called it, because Google never fully explained the mechanism behind it.

Eight years later, it got a name. In August 2026, Google’s Gary Illyes responded to a LinkedIn question about this scenario and described these URLs as alternate names. His explanation gives us a useful mental model for something international SEOs have been reverse-engineering for years: discovery, canonicalization, indexing, scoring, and serving are separate parts of the process, and a URL doesn’t necessarily have to pass through all of them independently to appear in search.

That distinction helps explain where hreflang actually fits in the process . More importantly, as search moves toward semantic retrieval and AI-generated answers , it raises a larger question for international websites: if multiple market pages contain essentially the same information, what makes any one of them uniquely valuable?

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