It appears that presubmit builds are no longer uploading to a stable location in GCS, therefore making the instructions https://github.com/flutter/flutter/blob/master/docs/engine/Testing-presubmit-Engine-PRs-with-the-Flutter-framework.md invalid. The GCS bucket seems to namespace the artifacts by build bucket ID now. We suspect this started with this change: https://flutter-review.googlesource.com/c/recipes/+/57140