And rebreak long lines.
This should take no effective change, just refactoring.
RemainAfterExit=yes
MountAPIVFS=yes
PrivateTmp=yes
-ExecStart=/bin/sh -c 'systemd-notify --ready; while ! grep -q -F MARKER /tmp/img/usr/lib/os-release; do sleep 0.1; done; mount | grep -e "/dev/mapper/${roothash}-verity" -e "/dev/mapper/loop[0-9]*-verity" | grep -q -F "nosuid"'
+ExecStart=/bin/sh -c ' \\
+ systemd-notify --ready; \\
+ while [[ ! -f /tmp/img/usr/lib/os-release ]] || ! grep -q -F MARKER /tmp/img/usr/lib/os-release; do \\
+ sleep 0.1; \\
+ done; \\
+ mount; \\
+ mount | grep -F "on /tmp/img type squashfs" | grep -q -F "nosuid"; \\
+'
EOF
systemctl start testservice-50d.service