On the Ibuildings techPortal site there's a retrospective of the Dutch PHP Conference from this year, 2011.
Before our memories get swamped by our daily lives, let's take a look back at the Dutch PHP Conference 2011. For me, two things stand out when I look back on this years DPC. One was the rate at which ideas were exchanged, both during the regular conference days and at the associated social events. [...] The other thing to stand out was the fact that many talks were not about PHP.
He goes on to talk about the ratios of PHP to non-PHP talks (only 37% were PHP-specific!) and breaks down the non-PHP talks into a few different categories including architecture, tooling, front end development and general framework updates. He also compares this to the PHP talks and came out with some interesting results.
For today's PHP development teams, generic software engineering principles and technologies allied to PHP have become part of their architectures and daily work routine. It is only logical that we want to know more about them and learn about new ones. It is no surprise then, that we see schedules at PHP conferences which include a good proportion of talks that are not directly about PHP itself.