The Log Message activity is used to write a diagnostic message at a specified level to the output panel, the log file, and Orchestrator1. The message can include custom log fields that are added by the Add Log Fields activity and removed by the Remove Log Fields activity2. In this case, the developer has added six log fields in the Add transaction log fields (Success) sequence and removed three of them in the Remove transaction log fields sequence. Therefore, the remaining three log fields (logF_TransactionField2, logF_TransactionID, and logF_TransactionStatus) will be displayed along with the default log fields (message, level, logType, timeStamp, fileName, processVersion, jobId, robotName, and machineId) when executing the Log Message Completed activity. The values of the log fields will be taken from the corresponding arguments of the Set Transaction Status activity.
References:
Add Log Fields activity documentation from UiPath
Remove Log Fields activity documentation from UiPath
Log Message activity documentation from UiPath