справочник по конфигурации DNF (DNF Configuration Reference)
Файлы (Files)
Cache Files
/var/cache/dnf
Main Configuration File
/etc/dnf/dnf.conf
Repository
/etc/yum.repos.d/
Variables
Any properly named file in /etc/dnf/vars is turned into a
variable named after the filename (or overrides any of the
above variables but those set from commandline). Filenames
may contain only alphanumeric characters and underscores
and be in lowercase. Variables are also read from
/etc/yum/vars for YUM compatibility reasons.