Quite a rare bug.

Last time Picard crashed with that error:

python[386466]: Traceback (most recent call last):
    File "/usr/lib/python3.13/site-packages/picard/ui/edittagdialog.py", line 271, in value_edited
        self._modified_tag()[row] = value
        ~~~~~~~~~~~~~~~~~~~~^^^^^
    IndexError: list assignment index out of range

systemd-coredump[434103]: Process 386466 (picard) of user 1000 terminated abnormally with signal 6/ABRT, processing...
systemd[1]: Started Process Core Dump (PID 434103/UID 0).
systemd-coredump[434106]: [🡕] Process 386466 (picard) of user 1000 dumped core.

The few times I got this error, it was when I was playing with multi-values tags.
In the GUI, I right clicked on a tag then "modify" (Alt+Maj+E). I edited several tags, and then changed the editing box to an already existing tag, and for an unknown reason there are 3 items in the list in the GUI:

1. original value
2. empty value
3. empty value with cursor
   Whatever action I do with the 2nd ("empty value") - that is modifying or deleting it - results in the above IndexError.

I tried my best to find a way to reproduce the error, in vain: I don't know why or when it happens, but it can happen.