As a user, the npm usage doesn't seem very prominent. On an npm's web page, there's a checkmark next to the version number on the right side that I hadn't paid any attention to before, with more information at the very bottom of the page. Here's an example. [3]

[1] https://blog.sigstore.dev/npm-provenance-ga/ [2] https://blog.sigstore.dev/homebrew-build-provenance/ [3] https://www.npmjs.com/package/fast-check