According to the comments, Part::slotSaveFeedList() is intended to back up the feeds.opml file the first time that it is to be overwritten. This is a bit ambiguous, but according to the code and the use of the m_backedUpList flag it should happen the first time the file is saved in a run of the Akregator application. However, this never happens because QFile::copy() will not overwrite an existing file.
The effect of that is that the file will be backed up the first time that Akregator is ever run by a new user, and no backup will then be taken ever again. Evan that backup is not very useful as it will be a copy of the default feed list.
This change removes the destination file before the backup copy is taken.