Where Can I Find The _sre.py Python Built-in Module?

I am studying the python regular expression (re.py) source code. In re.py they imported the module sre_compile: import sre_compile and I look at the module sre_compile there they

Solution 1:

_sre is the C-extension that implements most of the re module functionality. C-extensions usually do not have a __file__ attribute.

As such you are looking for the _sre.c source file instead.