In the paragraph below, the two occurrences of "systemd-journalctl" should be
changed to journalctl.

Paragraph:

Section 10.6.8, ���Debugging Services��� explains how to view log messages for a
given service. However, displaying log messages is not restricted to service
logs. You can also access and query the complete log messages written by
systemd���the so-called ���Journal���. Use the command systemd-journalctl to display
the complete log messages starting with the oldest entries. Refer to man 1
systemd-journalctl for options such as applying filters or changing the output
format.

Documentation Location:

10.6.2  System Log

https://doc.opensuse.org/documentation/leap/reference/html/book.opensuse.reference/cha.systemd.html#sec.boot.systemd.advanced.logging

Documentation Feature:

A nice feature addition to the html documentation would be to make any
reference to a man page active.  Fore example, "man 1 journalctl" would be an
active link to http://man7.org/linux/man-pages/man1/journalctl.1.html.

I'm not aware of opensuse having man pages online. Ubuntu does, kernel and
number of other locations.