Features: 0/10
Rather lacking on features sorry
Performance: 10/10
Still, not even a slight performance hit
Interface: 10/10
Size: 9/10
Could have been a little smaller, but still much smaller than many other extensions.
Documentation: 6/10
Well, no documentation, but it did exactly what it was supposed to straight away, so I guess there's no need?
So, overall: 7/10 (35/50)
Which makes this a good extension to have.

What more features do you need?
It already has 2 very important settings!

I know, documentation is a drag. I have a long todo list. Documentation on all my extensions is in there... somewhere

And I am working on a version that will have an even bigger file size. To make it do nothing even better needs a lot of code!

Hmm, more code eih..
define('PI',3.141592....);
And a nice little performance issue:
while(true){
$x = PI*37;
}

There we are, my little contribution