What will a cleanly interrupted restore with Déjà Dup have done?

The question title is vague partly because the documentation / help and UI are, but below I say what I need to know. Three days ago (2024-05-13, Mon) I started using Déjà Dup, got it to make a full backup of my home directory tree on a USB stick and told it to make weekly backups. Today (2024-05-16, Thu) I thought I had probably accidentally permanently deleted a file or even directory (Shift-Delete on the wrong side of a split screen in Dolphin!), and that this was a good chance to try out the restore function. I inserted the stick and started Déjà Dup from the (OpenSuse Leap) start menu, I do not know which I did first) and was surprised to see it said it was backing up, though I do not recall having said it should back up on Thursdays. I presumed it would be an incremental backup, and it did indeed take nothing like as long as the original backup. Once it was finished it exited, so I started it again and asked it to restore one directory sub-tree, worth about 28 out of 400 Gb, by selecting it in the appropriate dialogue. It stomped around silently for quite a while, asked for a password, stomped around a little more, then started saying it was restoring ... more or less everything, it seemed! Since I had just spent quite a long time tidying up, reorganising and freeing up space, I was alarmed, and eventually sent it a TERM signal, as I could find no way to stop it in its UI. Of course I specified to restore from the full backup, as I had already (probably) deleted before the incremental backup. This leaves me with a few relatively urgent questions: * Is there a chance that it has left something corrupt in the tree it was working on? * I.e. does it handle TERM cleanly? * Is there a log somewhere of what it actually did? * Was it really restoring all the files it said it was? * Was it going to revert some or all of my system to the state at the time of the full backup, losing recent changes? and a few more fundamental ones: * Is it possible to specify several files / directories to be restored, or select on other criteria such as time? — I saw no such options. * Is it possible to specify a policy when a file to be restored would overwrite a later change? * If not, how can one restore files to a directory on which one has worked? * What is its policy when a file to be backed up is in use? * Is there a good way of getting more insight into what it does, apart from reading the code? * Is there a good way or getting more control over the process? * Is there perhaps a different GUI tool offering me full control of the underlying functionality? (I am prepared but reluctant to learn `rsync and/or duplicity` and roll my own.) At first I quite liked the minimal nature of the UI, but now it seems to me to lack many essential options. I know one should RTFM, but this FM was F vague on many points. I have now turned off automatic backup, and may even deinstall this tool.