I could not find any reference in current HEAD to /system/test/. The information seems outdated.

2006/8/3, Breyten Ernsting <breyten@gmail.com >:
On 8/3/06, Khalid B <kb@2bits.com> wrote:
> It is worth including the change in this page http://drupal.org/node/56773
> to the standard .htaccess we distribute?

+1, but note that it blocks the fake phantom call for the clean urls,
so we need to fix that before it goes in :)