It is because that URL was already submitted after his passing with a short note from Apple. This is to submit a different story that has the same URL.
You can't submit a URL to HN twice - since the Steve Jobs tribute page had already been submitted, I'm assuming an arbitrary parameter was added to allow the URL to be reposted.
This page has already been submitted a few times (it's the same URL as his death announcement was posted on), so that needed to be added to get around the dupe-checker.
