Git doesn't support "orange"; use "yellow".

6e6508408b7ee7e595d657bba0fc30de076fae4c set the default colour for modified
files to:

    git config --get-color "gitsh.color.modified" "orange"

Unfortunately, there is no "orange". The colour has always been called
"yellow", it just looks orange in preferred terminal emulator colour scheme.

Oops.