Here's one more small cleanup that should have been in PR gh-28319. We eliminate stdout side-effects from importing the frozen __hello__ module, and update tests accordingly. We also move the module's source file into Lib/ from Toos/freeze/flag.py. https://bugs.python.org/issue45019
This directory contains the generated .h files for all the frozen modules. Python/frozen.c depends on these files. Note that, other than the required frozen modules, none of these files are committed into the repo. See Tools/scripts/freeze_modules.py for more info.