cpython

gh-151424: Fix impossible stack traces in `RemoteUnwinder(..., cache_frames=True)` by copying chunks on cache miss (#151426)

gh-151443: Fix documented default of `unittest.mock.mock_open`'s `read_data` parameter (#151444)

gh-151403: Fix use-after-free when an argv item's __fspath__ mutates args (GH-151404)

gh-77328: Update `base64` module RFC references to RFC 4648 (#151275)

Docs: Fix method directive signatures in `enum` docs (#151429)