Licensing
PHP is free software released under the PHP License, which insists that:
Products derived from this software may not be called "PHP", nor may "PHP" appear in their name, without prior written permission from group@php.net. You may indicate that your software works in conjunction with PHP by saying "Foo for PHP" instead of calling it "PHP Foo" or "phpfoo".This restriction on use of the name PHP makes it incompatible with the GNU General Public License (GPL).
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