The Source Set creation is part of running a reference pattern where the set of sources for the reference is created.
More on running reference patterns can be seen here: CMS - Dependencies - using Reference Patterns
Following is the set of loglines related to this task.
Excerpt Macro - Logs - Full Analysis Image for 83
CAST-MS-<date>-<time>.log.txt log file
Section of CAST-MS log file dealing with Create Source Set step as shown in the log above.
Starting Create Source Set
INF: 2018-10-23 16:41:50: starting Task Create source set for ref1
INF: 2018-10-23 16:41:51: Task message: Number of objects selected : 106
INF: 2018-10-23 16:41:51: No associated log file
INF: 2018-10-23 16:41:51: ending Task Create source set for ref1