Right, but the title strongly implies that the article is talking about executing PHP on the Pi.
I had the same reaction, I was hoping to hear about a problem solved by the Pi Zero, maybe configuration tweaks or something for PHP, it sounded almost like it was going to give a performance tip as far as the Pi Zero is concerned.
A great example of how a headline can tie barely related content into the latest trend / top-rated HN article to catch a few more page views / front-page votes... marketing!