> What is the problem between _Py_IDENTIFIER and multi-phase initialisation modules?
AFAIK there is no problem now, except possibly a race condition when initializing the identifiers.
It seems it's too easy to conflate porting to multi-phase initialization and getting rid of static state.
The problem will come with per-interpreter reference counting, or when the `str` class is no longer shared across all interpreters. For that, we'll need either per-interpreter identifiers, or solve the issue in another way.