DebianPts:docbook2x embeds the current date by default into generated manpages.

[[https://reproducible.debian.net/issues/timestamps_in_manpages_generated_by_docbook2x_issue.html|Known affected packages]]

= Solution =
Set a deterministic timestamp with the `--string-param header-3=...` parameter.

== Example ==
{{{
BUILD_DATE=$(shell dpkg-parsechangelog -S Date | LC_ALL=C date -u "+%d %B %Y" -f -)
...
docbook2x-man --string-param header-3="$(BUILD_DATE)" $input
}}}