Subject mostly tells the story. During a recent security update one of
the package updates ran /usr/sbin/update-mime. This is nominally okay,
but since no packages were added or removed, /etc/mailcap didn't need any
change, yet update-mime still insisted upon rewriting the file.
Updating the mtime on the file means backup tools want to save new copies
and this doesn't help. Security tools may also take note and need to be
molified.
Not a dire situation, but somewhat annoying. Example patch attached.