Thanks for the heads-up about the "10.16" issue, Marc. Sorry I missed that aspect when reviewing your fix as we had run into that "feature" before. I guess the idea was that it made it easier during the early days of Big Sur to build some products that were not expecting the version numbering change. In any case, it isn't an issue for the python.org macOS installer builds; we currently support two variants: universal2 which builds on 11 Big Sur (or later) with Tk 8.6.11 (or later); and the deprecated Intel-only variant which builds on 10.9 with Tk 8.6.8. After all the testing we've done, I'd prefer to not disturb the patches in place for the imminent release of 3.9.8 and a patched 3.10.0 installer; we will pick up the final versions when 8.6.12 releases. I am planning to use 8.6.12rc1 with the also imminent 3.11.0a2 to give it a little exposure but the 10.16 fix is also not an issue for it.