How to find out what file is on a particular sector

It turned out that the needed utility was mentioned right on the Ubuntu Rescue Remix (Ubuntu Rescue Remix was discontinued in 2012) front page: ddrutility

Homepage of ddrutility: https://sourceforge.net/projects/ddrutility/

The comment provided by rickhg12hs deserves a place as an answer - it's on the mark.

The ntfs-3g utilities provide some useful functionality. In my experience, the ntfscluster tool has an advantage over ddrutility in that it can stand alone, whereas ddru_ntfsfindbad requires a ddrescue logfile. Not a problem in the context of the OP - as long as the logfile is still available.

Try something like:

 ntfscluster -s 1048576 /dev/sda2

to identify what file occupies partition sector 1048576 of the NTFS partition /dev/sda2. If the drive has errors, you can try including the -f option, but weigh the results accordingly.

Because even the -q option for quiet output can be a bit chatty, consider redirecting stderr to /dev/null using 2>/dev/null so that only only the file details output to stdout are displayed.