Loading PyTorch checkpoint without extension

I downloaded one of the PyTorch checkpoints from ViViT on github but it has no extension. When I want to load it I face this error:

unpickling stack underflow

Another time I add .pth extension to the file but I received the same error. Also, I check the repository codes but it is not clear how they saved the checkpoints. How can I use and load this checkpoint.

It seems the repository uses dmvr which is based on TensorFlow.
The repository gives you some information about the checkpoints:

The following table contains pretrained ViViT models trained on various datasets. Checkpoints are provided as Scenic checkpoints compatible with Flax, and also as Tensorflow SavedModels for inference.