Set background color attribute.
These attributes set the none bright named colors. The white color is a grey brighter than the "bright black".
| 40 | black |
| 41 | red |
| 42 | green |
| 43 | yellow |
| 44 | blue |
| 45 | magenta |
| 46 | cyan |
| 47 | "white" |
In practice these colors can be customized or selected from a theme in most terminals. The exact values can vary wildly.
🛈 linuxvc has drivers that support monochrome mode, in which case the colors are ignored.