xdebug

xdebug.txt

sudo apt-get install php-xdebug
zend_extension="/usr/lib/php/20151012/xdebug.so"

php.ini:
zend_extension="/opt/lampp/lib/php/extensions/xdebug.so"
xdebug.remote_enable=1
xdebug.remote_host=127.0.0.1 
xdebug.remote_port=9000
xdebug.idekey=PHPSTORM


download from xdebug.org
extract to some folder
run phpize in that folder
./configure --enable-xdebug --with-php-config=/opt/lampp/bin/php-config
make
sudo cp modules/xdebug.so /opt/lampp/lib/php/extensions

File->Settings->Languages&Frameworks->PHP
select proper php language level
add new cli interpreter as /opt/lampp/bin/php

Set the url with ?XDEBUG_SESSION_START=PHPSTORM and set a header Cookie: XDEBUG_SESSION_START=PHPSTORM