Is there any list of the MAN (etc.) documentation installed?

[baldyeti]

As a kind of TOC for man pages, you might also want to give xman a try. Click on "Manual Page", then select one of the sections. All available entries are clickable and xman is a decent man page viewer.

[user unknown]

A toc wouldn't perhaps be of much help

Why?

Open a terminal/ console.
Type:

ls -R /usr/*/man

These are only a few of the man-pages.
In former times, there was a man-path - where is it gone?

To create an toc,

ls -R /usr/*/man  >~/man.toc

Perhaps there's a kind of toc/ db in /var/??

To find all dirs containing mans:

find / -name man -type d 2>/dev/null