Based on what the company has said it is the Clinical data and (Chemistry, Manufacturing and Controls (CMC) portions. The non-clinical portion was already submitted. I'm guessing the FDA breaks the submission into these 3 categories.
This likely isn't the level of detail you were looking for, so maybe someone more versed in the process can chime in also.

Here is a website that provides an overview of the BLA submission process.

https://www.thefdagroup.com/thefdgroup-blog/2...a-process/