Paste the below command into Terminal and press Enter.
sqlite3 ~/Library/Preferences/com.apple.LaunchServices.QuarantineEventsV* 'select LSQuarantineDataURLString from LSQuarantineEvent' > ~/Downloads/downloadhistory.txt
This places a text file called downloadhistory.txt in your Downloads folder. Open it to view its contents.
To prevent your Mac from tracking your downloads in the future, paste the below command into Terminal and press Enter.
defaults write com.apple.LaunchServices LSQuarantine -bool NO