Please don't do this when reproducing exploits. Yes, it's just source code, and yes, the url is dead. But it's still source code that, when compiled, will grab your real safari data and attempt to upload to a url that could be switched on.
There's a difference between repro'ing an exploit and weaponizing an exploit. alert(1) is generally the best thing to aim for, or even alert(some user data) to illustrate the point. Whereas upload(some user data, my server) is a bit too close to the moral equivalent of `rm -rf $HOME/*`: all of these illustrate the point, but rm'ing a homedir is generally not a great thing to have in your repro; ditto for uploading real user data.
exmaple.com was explicitly reserved for scenarios like this, which would accomplish the same thing safely.
It may seem like a pedantic point, but it was something I was taught as a pentester: don't weaponize exploits; simply reproduce them. So my instincts kicked in, and it's impossible not to mention it. (That said, I don't mean to make a fuss – it's not a big deal in this case.)
By the way, I found this post via the author's twitter: https://twitter.com/lapcatsoftware I've been following them for about a year now, and their tweets on Mac programming have been quite informative.