Document site-level changelog for multi-product docs sites

[devin-ai-integration]

Summary

Multi-product docs sites (those using the top-level products: key in docs.yml) can now have one shared changelog for the whole site. It's configured with a new top-level changelog: key next to products: and is served at the bare /changelog URL, outside any product slug and absent from the product switcher. Until now, the only way to get a shared changelog was a dedicated "Changelog" product hidden from the switcher with CSS; this replaces that brittle workaround with a first-class, opt-in configuration.

Implements docs for: feat(cli): add site-level changelog for multi-product docs sites (fern-api/fern#17737)
Implements docs for: feat(fdr): support site-level changelog on ProductGroupNode (fern-api/fern-platform#14420)

Pages changed

• fern/products/docs/pages/navigation/changelogs.mdx — new "Site-level changelog for multi-product sites" section: top-level changelog: example next to products:, /changelog URL, not in the switcher, requires products: (fern check rejects it otherwise), accepts the same options as a navigation changelog.
• fern/products/docs/pages/navigation/products.mdx — one sentence in the "Remove extra navigation from docs.yml" step noting the top-level changelog exception, linking to the new section.
• fern/products/docs/pages/changelog/2026-09-17.mdx — new Docs changelog entry (navigation, docs.yml).

Validation

• pre-commit run --files <changed>: Vale passes on the new content; the 2 errors reported in products.mdx (lines 171, 179) are pre-existing text not touched here.
• cd fern && npx --yes fern-api@5.59.0 check --warnings: 0 errors.

Link to Devin session: https://app.devin.ai/sessions/bcb138597f614759a6f550b0613d02f4
Open in Devin Desktop: https://app.devin.ai/desktop/session/bcb138597f614759a6f550b0613d02f4?variant=devin

[devin-ai-integration]

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[github-actions]

🌿 Preview your docs: https://fern-preview-devin-1789664949-site-level-changelog.docs.buildwithfern.com/learn

Here are the markdown pages you've updated:

• learn/docs/changelog/2026/9/17
• learn/docs/configuration/changelogs
• learn/docs/configuration/products