What is the purpose of a bronze layer in data engineering?

In general, the bronze architecture concept is used at the first step when data comes in and is stored in the original form with minimum transformation. The purpose is to keep source data for future review and/or future processing. When multiple sources are used, this layer can be very convenient as it allows teams to have a consistent history of the data prior to the application of cleansing rules. Data then can flow towards more sophisticated stages. The simpler the initial layer, the easier it will be to troubleshoot if it does not produce the results that are expected if there is a disconnect with the results downstream.