In order to automate prevention of ABI regressions in stable releases, we could create an automated ABI stability test generator and check the specific ABI test it generates into each specific release branch.

I'm envisioning the main branch only having a code generator that creates such a test, and the release branches only having the output of that as Lib/tests/release_X_Y_ABI_stability_test.py and a policy of never updating that within a release branch without *extreme* attention to detail.

Such updates wouldn't happen by default in our current workflow as they're unique and versioned in every release branch so automated backport PRs wouldn't touch them - leaving CI to run them and highlight failures on attempted backports to do inadvertently cause an ABI shift.