Php

You need to be more explicit, and you need to explain how it would fit into an integrated system. At present KA has one programming course that uses an odd dialect of javascript. From other posts and the FAQ, I think that their intent is:

HTML
CSS
javascript as used on web pages
python

php as used on web pages would fit here.

Unfortunately KA doesn't publish a road map of their intentions, so the above is speculative. (I am just a teacher, and do not speak for KA)