If LogFile is specified, the file is created at the start of the import, written to during the import, and then opened to a Log Window when the import finishes.
Here is a simple example where the DJIA components were imported but stocks above $100/share were excluded from the import. The log shows which those were.
The "Events" column in this case shows how many ex-dividend dates there were in this time period for each stock. If a custom event list is used, the count of those events would be shown here as well.