* nspawn: map foreign UID range through 1:1
+* a small tool that can do basic btrfs raid policy mgmt. i.e. gets started as
+ part of the initial transaction for some btrfs raid fs, waits for some time,
+ then puts message on screen (plymouth, console) that some devices apparently
+ are not showing up, then counts down, eventually set a flag somewhere, and
+ retriggers the fs is was invoked for, which causes the udev rules to rerun
+ that assemble the btrfs raid, but this time force degraded assembly.
+
+* systemd-repart: make useful to duplicate current OS onto a second disk, so
+ that we can sanely copy ESP contents, /usr/ images, and then set up btrfs
+ raid for the root fs to extend/mirror the existing install. This would be
+ very similar to the concept of live-install-through-btrfs-migration.
+
+* introduce /etc/boottab or so which lists block devices that bootctl +
+ kernel-install shall update the ESPs on (and register in EFI BootXYZ
+ variables), in addition to whatever is currently the booted /usr/.
+ systemd-sysupdate should also take it into consideration and update the
+ /usr/ images on all listed devices.
+
* replace all uses of fopen_temporary() by fopen_tmpfile_linkable() +
flink_tmpfile() and then get rid of fopen_temporary(). Benefit: use O_TMPFILE
pervasively, and avoid rename() wherever we can.