dart-sdk/pkg/js_runtime
..
lib/synced
test
analysis_options.yaml
OWNERS
pubspec.yaml
README.md

Package js_runtime:

This package contains code that is shared between the dart2js compiler and the dart2js runtime libraries.

Important: all code under the lib/synced/ must be kept in sync with the runtime at all times (in sdk/lib/_internal/js_runtime/lib/synced). The test/in_sync_test.dart test verifies this.