Internal Program Version: systemd  257.5

This library provides several of the systemd C APIs:

* sd-bus implements an alternative D-Bus client library that is
  relatively easy to use, very efficient and supports both classic
  D-Bus as well as kdbus as transport backend.

* sd-daemon(3): for system services (daemons) to report their status
  to systemd and to make easy use of socket-based activation logic

* sd-event is a generic event loop abstraction that is built around
  Linux epoll, but adds features such as event prioritization or
  efficient timer handling.

* sd-id128(3): generation and processing of 128-bit IDs

* sd-journal(3): API to submit and query journal log entries

* sd-login(3): APIs to introspect and monitor seat, login session and
  user status information on the local system.

https://www.freedesktop.org/wiki/Software/systemd