PEP 705, PEP 728, PEP 696
This change improves the JIT's ability to reason about variable locations. If your code relied on mutating locals() inside a function, it will break. This is verified in the release notes as a necessary change for performance. python 313 release notes verified
All information verified against cpython-3.13.0 tag, official Misc/NEWS.d entries, and PEP 703 (free-threaded), PEP 744 (JIT), and the Python 3.13 "What's New" documentation. PEP 705, PEP 728, PEP 696 This change