[masklinn]

That also goes both way: Pypy defaulted to ordered dicts a few years before cpython did.

[maxnoe]

The insertion order dict implementation actually comes from pypy

[masklinn]

The insertion order dict implementation comes from Raymond Hettinger who is amongst other things a core CPython developer. pypy pulled the trigger on using it first (and probably has optimisations CPython doesn't). PHP also used it before CPython did, IIRC. And possibly Rust (as the third-party indexmap).