ansi-color-faces-vector is a variable defined in `ansi-color.el'.
Its value is

[default bold default italic underline success warning error]

Faces used for SGR control sequences determining a face.
This vector holds the faces used for SGR control sequence parameters 0
to 7.

Parameter Description Face used by default
0 default default
1 bold bold
2 faint default
3 italic italic
4 underlined underline
5 slowly blinking success
6 rapidly blinking warning
7 negative image error

Note that the symbol `default' is special: It will not be combined
with the current face.

This vector is used by `ansi-color-make-color-map' to create a color
map. This color map is stored in the variable `ansi-color-map'.

You can customize this variable.