Right-click and sort by "Date Added" to see which original file the duplicate belongs to.
If your downloads folder is overflowing with files like 449 (1).mp4 , you can use these tips to stay organized: 449 (1)mp4
The suffix added by Windows or macOS because a file named "449.mp4" already exists in that same folder. Right-click and sort by "Date Added" to see
Use built-in tools like "Cleanup Recommendations" on Windows to find and delete these "(1)" duplicates automatically. 449 (1)mp4
When you see a name like this, it is usually the result of your operating system's feature.