FTR, reattempting the upgrade with overwrite-local temporarily activated in /etc/python/debian_config reveals the problematic file to be dropin.cache:
Preparing to replace python-twisted-core 8.1.0-1 (using .../python-twisted-core_8.1.0-2_all.deb) ... overwriting local files warning: already exists: /usr/lib/python2.5/site-packages/twisted/plugins/dropin.cache -> None -- Aaron M. Ucko, KB1CJC (amu at alum.mit.edu, ucko at debian.org) http://www.mit.edu/~amu/ | http://stuff.mit.edu/cgi/finger/[EMAIL PROTECTED] -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]