Hi Ralf,
why doesn't pacman change the permissions at package upgrade? ... Custom, unusual permissions may be required for a user's system.
Yes.
IMO permissions are similar to configurations. New configurations are required from time to time, but you don't want that a package upgrade does overwrite your configurations.
Say my first install of a package creates /etc/p.conf. I don't edit it. Then the package is upgraded; upstream provide an altered p.conf. I'd expect p.conf to be changed and I think that's what happens. Similarly, if the package made a directory on installation and I left its permissions untouched then an upstream change of permissions should flow down to me. Only if I've moved away from the old upstream should the permission-change be skipped. Perhaps there's another reason why pacman doesn't pass on upstream permission changes. -- Cheers, Ralph.