While the project was successfully installed on Drupal 9, running phpstan on it failed. This is usually caused by PHP interface mismatches, missing base classes or redefining global functions. In most cases this would mean the project would not run well in Drupal either. Run Upgrade Status or phpstan-drupal locally to reproduce the error and solve the problem in the project codebase.
Results are from dataset #136 from 2022-06-26T14:32. Report is ran by the Drupal Association regularly.