It's a CCleaner tool that helps you find and delete duplicate files on your PC:
The Duplicate Finder in CCleaner for Windows in Tools > Duplicate Finder can save you valuable hard drive space on your PC by deleting these types of unwanted files.
Locate duplicates of documents, videos, photos, and more:
These can appear over time and take up unnecessary space on your hard drive or can make organizing your files more complicated than it needs to be.
Search files via File Name, Size, Modified Date, and Content:
You can search for files using any of these categories in Duplicate Finder > Match by. Select the categories you want and then click Search to find the duplicate files. CCleaner shows you the results and lets you delete any unneeded files that it manages to find.