Migrating from VS Code, a developer depends on an extension that is published only on the Microsoft Marketplace, and it is missing from Cursor's Extensions panel. What is the most dependable way to get the same capability?

The principle — Cursor uses the Open VSX registry for third-party extensions rather than the Microsoft Marketplace. Most popular extensions are on Open VSX, but not every Marketplace extension is listed there, and the same publisher.extension name can point to different publishers or different code on the two registries. Where a widely used extension is unavailable on Open VSX, Cursor publishes a first-party Anysphere replacement.

Why the key is correct — Many popular VS Code extensions are available, and some Microsoft Marketplace-only extensions are replaced by audited Anysphere builds. So a missing publisher listing is a prompt to search for the Anysphere build by capability rather than by the publisher name you remember. Concluding that the capability is unsupported is the expensive mistake, because the replacement is usually sitting in the same panel under a different name.

Why the others are wrong — Shared VS Code lineage says nothing about which registry the panel queries, so restarting and searching again finds the same nothing. Matching identifiers across registries is exactly the risk to avoid, since the same name can carry another publisher's code. And an allowlist restricts installs to approved publishers rather than expanding the catalogue, so it cannot make a Marketplace-only extension appear.

Remember this — Absent from the panel means absent from Open VSX. Check for the Anysphere build before deciding a capability is missing.

Sources — Cursor's Extensions help documentation.