Publishers can pass some parameters using subId's (sub1, sub2, sub3, sub4, sub5). These parameters are optional. However, you can find this information in exported reports and use it for any analysis you like.
All you need is check sub account parameters in the export fields:
Then go to Export section and download the latest report:
Now you can find new columns with sub accounts (1) and sorting, filtering, etc. data from sub accounts (2):