Manual:$wgColorErrors

Debug: $wgColorErrors
Whether to color command-line error messages.
Introduced in version:1.6.0 (r13452)
Removed in version:1.17.0 (r70696)
Allowed values:(boolean)
Default value:true

Details edit

If true, some error messages will be colorized when running scripts on the command line; this can aid picking important things out when debugging. Ignored when running on Windows or when output is redirected to a file.