The info manual says:
<DEL> ('scroll-backward')
<PREVIOUS>
Shift the text in this window down. The inverse of
'scroll-forward'. If you are at the start of a node, <DEL> takes
you to the "previous" node, so that you can read an entire manual
from finish to start by repeating <DEL>. The default scroll size
can be changed by invoking the
('scroll-backward-page-only-set-window') command with a numeric
argument.
[...]
But this doesn't behave like that in the gnuplot manual from the
gnuplot-doc 5.4.1+dfsg1-1 Debian package: Go to "Bugs". This gives
------------------------------------------------------------
5 Bugs
******
Please e-mail bug reports to the gnuplot-bugs mailing list or upload the
report to the gnuplot web site on SourceForge. Please give complete
information on the version of gnuplot you are using and, if possible, a
test script that demonstrates the bug. See 'seeking-assistance'.
* Menu:
* known_limitations::
* External_libraries::
------------------------------------------------------------
Then do a scroll-backward (with the Backspace or PageUp key).
This gives:
------------------------------------------------------------
5.2 External libraries
======================
[...]
------------------------------------------------------------
which is not the "previous" node, but some later node.
-- System Information:
Debian Release: 11.0
APT prefers unstable-debug
APT policy: (500, 'unstable-debug'), (500, 'testing-security'), (500, 'stable-updates'), (500, 'unstable'), (500, 'testing'), (500, 'stable'), (1, 'experimental')
Architecture: amd64 (x86_64)
Kernel: Linux 5.10.0-7-amd64 (SMP w/8 CPU threads)
Kernel taint flags: TAINT_PROPRIETARY_MODULE, TAINT_OOT_MODULE, TAINT_UNSIGNED_MODULE
Locale: LANG=POSIX, LC_CTYPE=C.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled
Versions of packages info depends on:
ii install-info 6.7.0.dfsg.2-6
ii libc6 2.31-12
ii libtinfo6 6.2+20201114-2
info recommends no packages.
info suggests no packages.
-- no debconf information