Features:
+* timesyncd: when saving/restoring clock try to take boot time into account.
+ Specifically, along with the saved clock, store the current boot ID. When
+ starting, check if the boot id matches. If so, don't do anything (we are on
+ the same boot and clock just kept running anyway). If not, then read
+ CLOCK_BOOTTIME (which started at boot), and add it to the saved clock
+ timestamp, to compensate for the time we spent booting. If EFI timestamps are
+ available, also include that in the calculation. With this we'll then only
+ miss the time spent during shutdown after timesync stopped and before the
+ system actually reset.
+
+* systemd-stub: maybe store a "boot counter" in the ESP, and pass it down to
+ userspace to allow ordering boots. The counter would be monotonically
+ increased on every boot.
+
+* systemd-sysext: for sysext DDIs picked up via EFI stub, set much stricter
+ image policy by default
+
* systemd-dissect: maybe add "--attach" and "--detach" verbs which
synchronously attach a DDI to a loopback device but not actually mount them.