Context
Google Search Central documented how Googlebot retrieves only the first 2 MB of a supported non-PDF URL, including HTTP response headers, while PDF fetches have a 64 MB limit. Its October 29 correction clarified the header type. Unfetched bytes are not rendered or indexed.
What changed
Google published a detailed technical account of per-URL Googlebot fetch limits, truncated HTML processing, separate resource fetch budgets and stateless web rendering. An October 29, 2026 editorial correction specified response headers rather than request headers; it was not a product rollout.
Why it matters
Critical text, canonical metadata and structured data located beyond Googlebot's fetch cutoff may be invisible to Google Search indexing. This is a concrete upstream discoverability constraint for oversized pages.
Visibility OS interpretation
Visibility OS interpretation: crawl completeness is a prerequisite to potential search discovery, but this document does not demonstrate effects on AI Mode rankings, AI Overview citations, Gemini grounding or other AI crawlers.
What remains uncertain
How much of Google AI Mode or AI Overviews source retrieval depends on this Googlebot fetch behavior? Are fetch thresholds different for other Google product crawlers? Google says limits may change.