[Pages] Document Early Hints probes in Cloudflare logs

[ngayerie]

Summary

Add a new "Early Hints probes in logs" section to the Pages Early Hints page.

Cloudflare runs internal Early Hints probe requests on all Pages domains (including custom domains). These probes are always-on and cannot be disabled via the zone-level Early Hints setting. Without documentation, customers misread the resulting 504 log entries — which are internal cache misses, not origin errors — as real failures. This section documents the ClientRequestSource: earlyHintsCache log field identifier, explains the 504/200 semantics, provides a Log Explorer filter, and explains that Workers migration is the only path to disable Early Hints entirely on Pages.

DEE-3862

Documentation checklist

• Is there a changelog entry?
• The change adheres to the documentation style guide.
• Files which have changed name or location have been allocated redirects.

[cloudflare-docs-bot]

Review

✅ No issues found in commit 31d22bc.

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[cloudflare-docs-bot]

Review coverage

🟡 1 ownership area needs approval.

Suggested reviewers: @GregBrimble @irvinebroque

Needs approval	Eligible approvers	Suggested
pages	@aninibread, @GregBrimble, @irvinebroque, @MattieTK, @scottbuscemi, @WalshyDev, @cloudflare/product-owners	GregBrimble, irvinebroque

CODEOWNERS mappings for displayed areas (1)

Pattern	Owners
/src/content/docs/pages/	@aninibread, @GregBrimble, @irvinebroque, @MattieTK, @scottbuscemi, @WalshyDev, @cloudflare/product-owners

[github-actions]

Preview URL: https://31d22bc8.preview.developers.cloudflare.com
Preview Branch URL: https://dee-3862-pages-early-hints-probes.preview.developers.cloudflare.com

Files with changes (up to 15)

Original Link	Updated Link
https://developers.cloudflare.com/pages/configuration/early-hints/	https://dee-3862-pages-early-hints-probes.preview.developers.cloudflare.com/pages/configuration/early-hints/

[cloudflare-workers-and-pages]

🚀 Deploying Preview to Cloudflare 🚀

Preview URL: https://dee-3862-pages-early-hints-probes.previews.developers.cloudflare.com (commit 31d22bc)

This URL reflects your latest Preview deployment

Preview Deployments by commit

Status	Deployment URL	Commit	Updated (UTC)	See this deployment's details
Build: Success ✅ Deployment: Success ✅ View logs ↗	https://34b50522.previews.developers.cloudflare.com	31d22bc	2026-09-18T08:15:41.503Z	Visit the dashboard ↗
Build: Success ✅ Deployment: Success ✅ View logs ↗	https://4943ad36.previews.developers.cloudflare.com	b18066d	2026-09-17T17:12:06.006Z	Visit the dashboard ↗

[ngayerie]

Hi @WalshyDev
Would it be possible for you to review/approve this PR for Pages?
Thanks!