The raw blockchain data is not optimized for data analytics. In order to make the data more accessible, we index and decode the raw transaction data and repackage some of the data for better analytics performance. These newly formed data sets are called Data source.
There are two types of data sources: basic and customized. The basic data sources include Transactions, and Contracts. And everyone has access to them. The customized data sources are typically tailored for unique use cases and are usually optimizations to avoid complicated data correlations in our backend. Customers can request to make those data sources and we sometime publish additional data sources if there are popular demands in certain areas.