Featurization using identifier column

Can you kindly provide more information on the below mentioned under the featurization step:
https://docs.microsoft.com/en-us/azure/machine-learning/how-to-auto-train-forecast#configure-experiment

"Create features based on time series identifiers to enable fixed effects across different series"

What kind of features are these? Can you provide a simple example?
Do you have any literature references?

Thank you for your help

從連結的 Azure Machine Learning AutoML forecasting 文件開始，找到關於以時間序列識別碼為基礎的特徵之引用指南。完成的標準是文件說明這些特徵是什麼、包含一個簡單範例，並提供相關的文獻參考。

由索引模型根據 Issue 內容生成。