It’s the first 16 colors of the 256 set. Most current graphical terminals support the latter, but they only expose the first 16 in their configuration. So using

It’s the first 16 colors of the 256 set. Most current graphical terminals support the latter, but they only expose the first 16 in their configuration. So using them makes your software completely customizable. I believe the tty console only use the first 8.