Summary
Vercel launched Protected Source Maps so browser .map files return 404 to the public while staying available to authenticated team members. The feature is enabled by default for new projects and can be turned on for existing ones without redeploying.
What changed
Vercel introduced Protected Source Maps to restrict production browser source maps to authenticated team access.
Why it matters
This reduces a common exposure point where source maps aid debugging but also reveal readable production code. Shipping it as a platform default suggests source-map protection is becoming baseline hygiene.
Evidence excerpt
Vercel says Protected Source Maps put browser .map files behind authentication, with new projects enabled by default.