You're right pop
Here is what I see.
In log of apt (file /var/log/apt/term.log) I see the following :
réparation du dépaquetage de .../27-dokuwiki_0.0.20180422.a-2.1_all.deb ...
Dépaquetage de dokuwiki (0.0.20180422.a-2.1) ...
...
Paramétrage de dokuwiki (0.0.20180422.a-2.1) ...
Creating config file /etc/dokuwiki/htaccess with new version
WARNING: tempfile is deprecated; consider using mktemp instead.
Creating config file /etc/dokuwiki/local.php with new version
WARNING: tempfile is deprecated; consider using mktemp instead.
Creating config file /var/lib/dokuwiki/acl/acl.auth.php with new version
WARNING: tempfile is deprecated; consider using mktemp instead.
Creating config file /var/lib/dokuwiki/acl/users.auth.php with new version
WARNING: tempfile is deprecated; consider using mktemp instead.
Creating config file /etc/dokuwiki/apache.conf with new version
WARNING: tempfile is deprecated; consider using mktemp instead.
Creating config file /etc/dokuwiki/lighttpd.conf with new version
apache2_invoke: Enable configuration dokuwiki
And If I search for file install.php, I see these two files :
$ sudo find / -type f -name 'install.php' -ls
11176133 20 -rw-r--r-- 1 root root 19233 mai 3 2018 /usr/share/dokuwiki/install.php
3157195 20 -rw-r--r-- 1 root root 19233 mai 3 2018 /timeshift/snapshots/2023-03-17_08-00-01/localhost/usr/share/dokuwiki/install.php
So, it's not exactly the same of ubuntu package.