The config for macos-12-arm64-developer-build and macos-universal-on-arm64 are missing python3 html5lib somehow. We do not know why but it has been causing issues, first in that qtwebengine is not building due to missing dependencies and then qtwebview not working the same due to no qtwebengine.

See http://coin.intra.qt.io/coin/api/log/qt/qtwebengine/c8218fe63b840508186deeb069dc0511408ad01d/MacOSMacOS_12arm64MacOSMacOS_12x86_64-arm64Clangqtci-macos-12-arm64UseConfigure_WarningsAreErrors/5e17755d9e885272d1722ca33f1b5c44fb1c6528/build_1693612576/log.txt.gz and

http://coin.intra.qt.io/coin/api/log/qt/qtwebengine/c8218fe63b840508186deeb069dc0511408ad01d/MacOSMacOS_12arm64MacOSMacOS_12arm64Clangqtci-macos-12-arm64UseConfigure_WarningsAreErrors/a0c159c10681c14187aeecd10684955e07df84cb/build_1693612667/log.txt.gz

The issue predates those by quite a while. Perhaps we saw it first two weeks ago when you were investigating new qtwebview failures.