Explain the rdl in the SSRS Application?

In SQL SERVER REPORTING SERVICES, rdl stands for report definition language. Usually, developers create the report and mostly they used the GUI part to create it. We can add new items, we can embed data sources, parameter much more to our report.

In the background reports, convert everything into the rdl file. This is the file extension of your report. Follow below snapshots:

If you try to open the rdl file in any of the text editors it will look like below:  

As discussed previously, above is a screenshot for the rdl file which contains the definition of data sources and datasets as well