The function LogDebug (Messsage) writes into the eBiss log with log level 'Debug'. So that the message will not be written to the log in case of a normal job run. It will only be visible in case of mapping debugger run or if the log level of the job was changed to debug.
LogDebug (Message)
LogDebug(concat('Set TargetFrameVariable for filename with value: ', XVar('fn'))
Write every 5000 log call:
LogProgress('Do step number {0}.', 5000)