The devuan policy about systemd shims and systemd in devuan as been already exaustively discussed many times, and can i reassume it as follow:

Devuan will not work to support systemd and will not work against it. We will not do any effort to support it, if someone want to work to package it in a way where it works WITHOUT needs support for any other package depending on it, we will consider to add it as an option, but we will NOT accept it if it ask us to put it in dependency tree.
As for how it work, this policy put effectively it in the "we will not support it" list ad systemd without dependecy to it is like vaporware.

For shims, we will not introduce shims, as the work to trace abi from systemd components make it just a shit. We will optionally consider to reimplement some funcionalities we consider usefull from systemd, but in a unix/kiss way, so, probably without dbus, or not compatible with systemd: we want to have the few good funcionality that are present in systemd, but we want them better implemented.
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nextime