Performance of Python programs has been a major focus of development for the language over the last five years or so; the Faster CPython project has been a big part of that effort. One of its subprojects is to add an experimental just-in-time (JIT) compiler to the language; at last year's PyCon US, project member Brandt Bucher gave an introduction to the copy-and-patch JIT compiler. At PyCon US 2025, he followed that up with a talk on "What they don't tell you about building a JIT compiler for...