Platform.packageConfig in dart:core

Isolate.packageConfig in dart:isolate

Platform.packageConfig in package:platform

If you are using the package:platform package, note that regardless of whether
you are using the packageRoot API or not, older versions of that package are
not compatible with Dart 2.16 and later, as they depend on the now removed
packageRoot API. You may see an error like this when attempting to run your
app:

To resolve that, upgrade to version 3.1.0 or later of package:platform by
upgrading the constraint in your pubspec.yaml file:

dependencies

platform

^3.1.0

References

Relevant PRs:

Removed from the Dart libraries in #47769

Removed from package:platform in PR #38