In general in legacy, 3 areas of Perform: Job level (Configuration tab), Record Level (Records tab), Field Level (Data tab). Your screen shot is at Job Level but Record and Field level may also be relevant depending on what you're trying to troubleshoot.
KRONOS_FORMAT_START is a block of code (not a file) inside the PRWVI2 program located in the mas90\PR folder. On my 4.50 PU6 that block is checking the P/RABC (ABC=company) record in SY0CTL at 35,1 to see if J/C is integrated in P/R Options. In short it sets a J/C integration flag and nothing else.
There are some other blocks in PRWVI2 like KRONOS_VALIDATE_ADDL_RECORDS and KRONOS_ADDL_RECORDS that appear to do more stuff but they aren't in your screen shot. Maybe they are referenced in the Peform button under Records tab or Data tab.