dart-sdk/tools/dart2js/sourceMapViewer
..
bin
web
pubspec.yaml
README.TXT

This program serves a visualization of a JavaScript source map file generated
by dart2js or pub.

Run 'pub build' to build the application.

Usage: dart --package-root=packages/ bin/source_map_viewer.dart <path to map file>.

The default system browser is started and pointed to the viewer if available.