These options let you control which file operations Opus will keep a log of. The log can be quite handy at times - anyone who's ever dropped files into the wrong folder by mistake and then spent 20 minutes looking for them will know what we're talking about! You can view the file log by selecting the Logs / File Log command from the Help menu.
Log file functions: This option enables the file function log, and lets you specify the maximum number of events Opus will remember.
File Function Logging Level: This lets you select the amount of detail Opus stores in the file function log. Standard will only log copies and moves initiated by drag and drop, and delete operations. Maximum will log everything and Custom lets you choose exactly what operations to log.