It works for me:
curl http://git-01.antares3000.com/.well-known/test-file-2345
test file 2345
Now we go one further (closer to a real challenge file request):
mkdir /var/www/letsencrypt/.well-known/acme-challenge
echo "test file 3456" > /var/www/letsencrypt/.well-known/acme-challenge/test-file-3456