General developer forum

There is no such list outside of Moodle. Any such list would rapidly go out of date, and would not account for any third-pary plugins you have installed.

Instead, the Moodle admin screens themselves form such a list, with all the settings nicely grouped. If you look at them, you will see that every setting comes with a description that tells you what that setting does.

If you really wanted, it might be possible to write a simple plugin (e.g. an admin tool https://docs.moodle.org/dev/Admin_tools) which outputs a list of all the settings and what they mean.

Just to add to Tim's reply, Moodle has a log of all configuration changes, and who made them - which is especially great with multiple Administrators.  So it's pretty easy to save this and use as your document of what changed, when, and who by

A simple export of config and config_plugins will show you a list with all the moodle and plugins settings and its value.

I used this solution in some projects to keep a record of the settings.

What you get is only the setting name, not a description. Then you must cross the tables information with the moodle language strings to get the description. That could be more complex and will require some coding. A local plugin for it would be great.

The changes tracking can be do it exporting config_log table as Stuart mentioned. With the right query you can get the list sorted by plugin and date.