Is that for an incomplete torrent? Usually bittorrent clients mark incomplete parts of a torrent download with a different filename extension.
Also IIRC ktorrent creates folders ~/.local/share/ktorrent/tor#/ where "tor#" is one of "tor1", "tor2" "tor3" where it keeps track of the currently active torrents.
Not sure if that is what you are referring to, as you're missing some context information where exactly those tor1,tor2,tor3 etc are actually created (in what folder).
But your question is probably better suited for the KDE forums, where you already asked a similar question, but about konqueror:
https://forum.kde.org/viewtopic.php?f=235&t=164948