Performance tools
Composer overload class
Allow to overload autoloaded classes, to include your files instead of supposed ones.
steevanb/composer-overload-class
PHP backtrace
Show nice equivalent to debug_backtrace(), with caller, code preview etc.
steevanb/php-backtrace
Composer autoload infos
View Composer autoload informations: included files, autoloaded classes etc.
huttopia/composer-autoload-infos
Blackfire
Profile & optimize PHP apps.
blackfire.io