Is YOLO model using a validation set for pure training purpose?

For what concerns training, validation and test dataset I think there is a little bit of confusion in literature terminology.

I'm using this repo to train a model on custom 9 classes: https://github.com/ultralytics/yolov3 I don't understand if here the validation set is used in the training process (i.e. tune hyperparameters, etc..) or is used only to calculate some metrics (so as a test set of UNSEEN data).

Could anyone help me? Thank you.