alias : "Alias of the dataset. If set, the ‘alias : dataset ID’ key-value pair will be set under the hyperparameters section ‘Datasets’"

I have to concede that I found that description a bit vague at first but if you check that https://clear.ml/docs/latest/docs/clearml_data/best_practices#organize-datasets-for-easier-access you see that:

"In cases where you use a dataset in a task (e.g. consuming a dataset), you can easily track which dataset the task is using by using Dataset.get 's alias parameter. Pass alias=<dataset_alias_string> , and the task using the dataset will store the dataset’s ID in the dataset_alias_string parameter under the task's CONFIGURATION > HYPERPARAMETERS > Datasets section."