Most Mac OS X users probably never knew about this, but it is the truth. Your Mac computer keeps a running log of all downloads you have made with it from whenever you first made a download and you can view the log inputting a set of code into the terminal application.
In fact, your Mac logs everything that goes into the Download folder and to view the download documented log on your Mac, simply go to your Applications > Utility and launch Terminal. Then copy paste the below code and hit Enter.
sqlite3 ~/Library/Preferences/com.apple.LaunchServices.QuarantineEventsV* 'select LSQuarantineDataURLString from LSQuarantineEvent'
This would display a saved log of all the files you must have downloaded in the history of your Mac life. If you feel uncomfortable with this, you can easily clear it using the below code.
sqlite3 ~/Library/Preferences/com.apple.LaunchServices.QuarantineEventsV* 'delete from LSQuarantineEvent'
The above code would clear out the download logs. To confirm if it cleared, try running the first code again on Terminal and see if the download log would display. If it doesn’t, then you did it right.