Shows that source map support is not part of JavaScript itself. It's part of external tools like DevTools
https://greggman.github.io/sourcemap-test/
This example compiles Typescript to JavaScript with a source map. The code throws in a function in a module.
Notice that the stack trace returned to JavaScript shows JavaScript file names and line numbers where as in DevTools itself, it shows the source-map file names and line numbers.
Source Map support is entirely external to JavaScript itself.