Where can I find the logic that lays behind the copy filter

Hello people

One colleague of mine is asking me why a specific contract number was not copied after a TDTIM copy.

The first answer that came to my mind was “because of the time slice parameter”

But if I look at the records on table EKKO I find lots of contracts older that the “missing” one.

So, my question is: Where can I find the logic that lays behind the copy filter?

This is as far as I could get:

I know that the migration object name is E4_EKKO (or at least I suppose so).

Then via transaction cnv_mbt_menu I found the report CNVMBTSELREF

  
  But I wasn’t able to find anything related to EKKO.

So, my question is: How can I find the filtering criteria used during the TDTIM copies for a certain table?