This is about PHP code (i.e. written in the scripting language, PHP), not the PHP interpreter.

Since it's a scripting language, your build artifacts will be one of:

- .diff / .patch

- .zip / .tar / .tar.gz

- .phar (rarely)

Of these, only the last (PHP Archives) is mildly persnickety for build reproducibility. But it's easily fixed: https://github.com/paragonie/sodium_compat/blob/08ab867bbb6a...