ansi-color-for-comint-mode is a variable defined in `ansi-color.el'.
Its value is

Determines what to do with comint output.
If nil, do nothing.
If the symbol `filter', then filter all SGR control sequences.
If anything else (such as t), then translate SGR control sequences
into text properties.

In order for this to have any effect, `ansi-color-process-output' must
be in `comint-output-filter-functions'.

This can be used to enable colorized ls --color=yes output
in shell buffers. You set this variable by calling one of:
M-x ansi-color-for-comint-mode-on
M-x ansi-color-for-comint-mode-off
M-x ansi-color-for-comint-mode-filter

You can customize this variable.

This variable was introduced, or its default value was changed, in version 23.2 of Emacs.