We always try to improve the code structure and also automate checks for desired CGL (coding guidelines) in pull requests. A significant change is coming for these coding guidelines.
One of the biggest inconsistencies in PHP was array syntax. Function uses (), arrays uses  and (). Since PHP 5.4 short array syntax works in all array declarations. Our coding style guidelines will change to require the shorthand syntax.
"Is NULL" should be compared via if NULL === $variable. No more calls to "is_null()" and other functions that can be compared using type comparison.
Right now we test for example the space between if and (, but we have no test for = in a variable assignment. Checks have been added for these smaller formatting requirements.
Note: Most listed changes already perfectly in code and done by most IDEs.