You can open the manifest files in Notepad. The first line will look like this:
{“ManifestFileVersion”:“007000000000”,“bIsFileData”:false,“AppID”:“172156000000”,“AppNameString”:“Card_4.0”,“BuildVersionString”:“4.0.2-2047835+++depot+UE4-Releases+4.0-Windows”,
Note the Card_4.0, that is the project name. In this case, the Memory Card game. That will help you identify which project each manifest is for.
Cheers!