I just failed this audit answer:
You can use ClickMonitorDDC http://clickmonitorddc.bplaced.net this is a great tool for adjusting brightness and contrast of external monitors, but you can also adjust brightness of internal LCD, and this tool has an option (set by default) to use the same brightness for on battery and plugged in. You do not have to really work with this tool, simply run it once, there will be autostart (set by default), and the tool sits silently in the taskbar, but recognizes the change between on battery or plugged in, and it will ensure always same brightness.
As far as I can tell it:
Answers the question
It is not spam (ClickMonitorDDC is freeware)
Meets the requirements for recommending software (How do I recommend software)
Although it has been downvoted (and deleted) it is not a bad answer and should not be used for reviews.
It is not clear why it was deleted.