However, due to the presence of so many accounts even with the default configuration as is I thought that either Debian or Kali Documentation would provide a descriptive list of users alongside a short comment on what they do. I checked and if such list exists and if it does I have not found it.

It's probably not documented, but there's not much we can do. Writing such a documentation right now would take quite some time, and then would need ongoing maintenance. The list of users in /etc/password is not "static", a good part of those users are created when packages are installed or upgraded. New versions of some packages might create a new users, or not create a user anymore. And the lists of packages installed in a Kali system is not static either, it changes constantly as Kali is a rolling distro. So we'd need to review and update this documentation for every release: we don't have the bandwidth for that.

Also, it's standard practice that a service doesn't run as root, but instead a user is created upon installation (also called "system user"), and the service runs as this particular user. As a result, in a fully-fledged desktop environment like Kali Linux: a lot of packages are pre-installed, a lot of services are installed, and as a consequence a lot of system users are already created. It's really standard, there's nothing special about Kali here, and anyone familiar with Linux systems (at least Debian) won't find anything surprising. I don't know how it looks like by default in other distros though, but I'd expect a pretty similar passwd file

All in all, thanks for taking the time to write this bug report, but it's really not something actionable for us. Sorry.