Where is the source code of the PHP engine?

Where is the source code of the PHP engine? Does anyone know this problem? Source code of php.exe1_php-win.exe or php5apache2_2.dll. Is it officially available?

Reply to discussion (solution)

Php has always been open source and developed by C. See git.php.net

You can see it by downloading the source code package.
However, the core code of php for window is in lib, and all you can see is the call to it.

You can see it by downloading the source code package.
However, the core code of php for window is in lib, and all you can see is the call to it.
I have not found the specific page. can you tell me?

You can see it by downloading the source code package.
However, the core code of php for window is in lib, and all you can see is the call to it.

The core code of php for window. I didn't find the specific page. can you tell me?

Http://www.php.net/downloads.php

For example, if you enter Windows 5.4.19 binaries and source
Download source code [20.86 MB]
And so on.

The core of php is the zend directory under php.