The log is a text file named PinballY.log, located in the main PinballY program folder. PinballY automatically creates this file each time you run the program, and writes miscellaneous status messages to the file throughout the session. The log file is mostly for troubleshooting purposes; it has details on what the program was attempting to do, such as which directories it scanned for games and media files, what happened when it tried to load various external DLLs or access third-party programs, etc. You can control which types of status messages the system writes to the file via the program's main Options dialog.
logfile.log(formatString, ...): If the first argument to logfile.log() is a string, and it contains one or more "printf"-style "%" format codes, logfile.log() interprets it as a format string with substitution variables. Each "%" code is replaced with a formatted version of the corresponding argument from the arguments list, in left-to-right order. This uses the same formatting rules as console.log().