I noticed some other things being unexpected enabled by preset-all, e.g.
msmtpd.service, systemd-networkd.socket, reboot.target.
I think this shows relevant packages:
https://codesearch.debian.net/search?q=dh_.*systemd.*--no-enable&literal=0&page=29&perpkg=1
$ curl -s
https://codesearch.debian.net/results/460eb7b7b3635bc8/packages.txt | sort | fmt
2ping 389-ds-base acmetool acpid amavisd-new anope aprx argonaut
argus-clients balboa bdii beanstalkd bind9 bit-babbler bitlbee
booth btrfsmaintenance buildbot burp burrow canid chasquid
conserver consul corosync-qdevice csync2 davmail ddclient debhelper
dhcpy6d direwolf dogtag-pki dovecot drbd-utils fetch-crl fever fio
freeipa fwknop game-data-packager gamemode gfarm globus-gatekeeper
globus-gridftp-server globus-scheduler-event-generator glusterfs
golang-github-containernetworking-plugins gpsd graphite-carbon hdapsd
hylafax ifupdown init-system-helpers interimap ipmitool ipmiutil iwd
jupyter-notebook knockd libcircle-be-perl libosmo-sccp linux lirc
lizardfs logdata-anomaly-miner mailavenger mailgraph mariadb-10.5
mediawiki minissdpd miniupnpd moosefs mopidy mpd msmtp myproxy natlog
netscript-2.4 nextepc nftables nomad nordugrid-arc onak open-iscsi
openbgpd openssh osmo-bsc osmo-bts osmo-ggsn osmo-hlr osmo-iuh
osmo-mgw osmo-msc osmo-pcu osmo-sgsn osmo-trx packagekit pagure pgcluu
phosh pmacct postfwd powertop pptpd prelude-correlator prelude-lml
prelude-manager proftpd-dfsg public-inbox puppet qemu radicale rauc rsync
rtkit rygel sane-backends sanlock sbws slinkwatch sniproxy spamassassin
speech-dispatcher speech-dispatcher-contrib srslte stenographer syncplay
systemd-bootchart tcpcrypt teeworlds thinkfan trojan tryton-server
umtp-responder upower vanguards vdirsyncer voms w1retap wesnoth-1.14
xpra xscreensaver ypbind-mt ypserv zeroc-ice znc zoneminder
That suggests mariadb@.service would be affected, but
testing indicates otherwise:
$ mmdebstrap sid /dev/null --include=init,mariadb-server
--customize-hook='systemctl --root=$1 preset-all' --logfile=tmp.log
$ grep mariadb tmp.log
[no matches]
So I dunno!
