Can't make sense of encoding for a downloadable AutoTokenizer
## Environment info
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- `transformers` version: 4.2.2

### Who can help

Probably @n1t0 or @LysandreJik (AutoTokenizer)

## To reproduce

Steps to reproduce the behavior:

1. Boot up an AutoTokenizer using `AutoTokenizer.from_pretrained("sberbank-ai/rugpt3small_based_on_gpt2")`
2. Execute `tokenizer.get_vocab()`

The vocabulary contains gibberish instead of Russian tokens (yet the model works fine):

![image](https://user-images.githubusercontent.com/31738272/106778421-03fc8200-6657-11eb-8f24-48daad35ff16.png)

How do I decode and read the actual tokens?
This issue has been automatically marked as stale and been closed because it has not had recent activity. Thank you for your contributions.

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