These two hashes should be the same.
PS C:\Users\john> flutter --version
Flutter 3.28.0-2.0.pre.38547 • channel master • https://github.com/flutter/flutter.git
Framework • revision 8ad15cd81e (3 hours ago) • 2024-12-19 15:52:54 -0800
Engine • revision b79ee9282c
Tools • Dart 3.7.0 (build 3.7.0-260.0.dev) • DevTools 2.41.0
The bin\internal\engine.version and bin\cache\engine-dart-sdk.stamp files are the the same value: b79ee9282c3403197dece9dfeb82a90abe85a5f3 and yet:
git -C "$flutterRoot" merge-base HEAD origin/master
8ad15cd81e4cd2ad86524a8afa7021ea51c09169