Load_dataset 'blob' vs 'tree'

I receive error message : "FileNotFoundError: Couldn’t find file at https://huggingface.co/datasets/user/mydatasetname/tree/main/data/train.csv " when using ‘dataset = load_dataset(“user/mydatasetname”)’
loading custom dataset in colab

when I check the url with ‘blob’ instead of ‘tree’ word in the url, with ‘blob’ there is no 401 error message.

‘tree/main/data/train.csv’ VS ‘blob/main/data/train.csv’

why does load_dataset() use url ‘tree’ instead of ‘blob’ ?

to reproduce:

I put these code in colab:

!pip install datasets
from datasets import DatasetDict, load_dataset
!pip install huggingface_hub
!huggingface-cli login
from huggingface_hub import notebook_login

dataset = DatasetDict()

dataset = load_dataset(“user/custom dataset”, split=“train”, use_auth_token=True)

when logging in:

" Token is valid (permission: write).

Your token has been saved in your configured git credential helpers (store).

Your token has been saved to /root/.cache/huggingface/token

Login successful"