I wonder whether the target audience here is developers who want to build a new PHP application from scratch for GAE, or just people who want to install Wordpress? Using GAE adds a development/deployment step, but the lack of deployment fuss is the primary advantage PHP has over anything else.

I'm also slightly alarmed that the PHP examples use htmlspecialchars and nothing else. The Python documentation has a whole section on templating with an example autoescaping setup using Jinja2.