what is the difference in the submission_models?

[Altrouge7]

The different models 'SAC_a13', 'SAC_f3','SAC,f4',....,'SAC_c8", is there any difference between them?
Are these models trained with these forecaster?
I just run the train_sac.py but the result is bad. And in train_sac.py , there is not forecaster used during training.
Hope to get your answer, thank you very much。