What is settingsctl?
settingsctl is a utility that aims to provide a common interface to desktop settings (think power, appearance, etc.) in different desktops, which usually have differing methods to configure these.
This was also the aim of the xdg-settings project. But that failed.
What settings are available?
You will be able to configure whatever you can through the desktop environment's method (settings manager etc).
See the Available settings.
How do I use this?
See the tutorial.
How do I install this?
See the installation guide.
How do I contribue?
Please see the "Contributing" section in the README.
What language is this written in?
Python 3.
Why not xdg-settings?