Postfixadmin does not include the "INSTALL.TXT".

[Christopher C. Petro]

When you install postfixadmin there is a README.Debian file that contains:
-----
Where to get help
=================
The first stop would be the Postfixadmin Website, Forum or IRC channel.

See :
 - http://postfixadmin.sf.net
 - #postfixadmin on irc.freenode.net
-----

The first line redirects to a https://postfixadmin.sourceforge.io/, which then says:
-----
Installation

Please follow INSTALL.TXT (shipped with PostfixAdmin).
-----

This file is nowhere to be found in the /usr/share/doc/postfixadmin directory:

root@mailserver:/usr/share/doc/postfixadmin# find ./ | grep -i install.txt
root@mailserver:/usr/share/doc/postfixadmin#

Description: Ubuntu 20.04.3 LTS
Release: 20.04

apt-cache policy postfixadmin
postfixadmin:
  Installed: 3.2.1-3
  Candidate: 3.2.1-3
  Version table:
 *** 3.2.1-3 500
        500 http://us.archive.ubuntu.com/ubuntu focal/universe amd64 Packages
        100 /var/lib/dpkg/status