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Even if the lineage dies with PHP, that pulls in Facebook and WordPress.

Smarty could possibly take credit for inspiring some of the template engines out there also.

I still write and actually still (sorta-kinda) like PHP, but there's no major concept/feature I can think of that's intrinsic to PHP rather than inherited from other languages. The Perl (and general "C-like language" influence is notable, and as PHP has matured it's started to feel ever more like Java. ("To write a simple PHP server app, first just initialize your PSR-11 compatible dependency injection container and add your PSR-7 compatible HTTP request/response handlers to it...")

The mixed code/template capability seems to have led to JSX.

React(Js framework) is close to PHP as a concept. Facebook's team had to take ideas from their exisitng code. With JSX, we could potentially call it a new language.

E4X (https://en.wikipedia.org/wiki/ECMAScript_for_XML) is also a likely inspiration for JSX.