Just wanted to chime in with this upstream issue: https://github.com/jonls/redshift/issues/672
It seems to me, like something along this fix, would be enough: https://salsa.debian.org/debian/redshift/-/merge_requests/4/diffs +owner @{HOME}/.config/redshift/redshift.conf r, Just discovered this while migrating to bullseye, this does essentially break redshift on bullseye, if you use a config-file at the default location. -- Davralin