I just installed openSUSE-Tumbleweed-DVD-x86_64-Snapshot20190313-Media.iso on my local workstation with disabled online repos (same as http://d502.qam.suse.de/tests/1262#step/online_repos/1) and desktop gnome (same as http://d502.qam.suse.de/tests/1262#step/system_role/3) and, as expected, exim is installed instead of postfix (see screenshot above). openQA reg test: http://d502.qam.suse.de/tests/1263#step/evolution_prepare_servers/18