From the source
Hugging Face introduces chat templates as a standard attribute in tokenizers to preserve the correct chat format used during model training, preventing silent performance degradation from incorrect formatting.
From the source
From the source

Hugging Face introduces chat templates as a standard attribute in tokenizers to preserve the correct chat format used during model training, preventing silent performance degradation from incorrect formatting.
From the source
Hugging Face tokenizers now have a chat_template attribute that can be used to save the chat format the model was trained with.
huggingface.co