Update: GitHub has released a macos-26-intel image.
macOS 26 Tahoe itself will be supported by Apple until ~September 2028, however, GitHub only supports two OS images (plus a beta), so macos-26-intel will probably be dropped a few months before macOS 26 EOL.
Anyway, we’ll switch to macos-26-intel in due course (#145098) to keep testing on GitHub Actions for a bit longer and catch things before merge, and also keep it at tier 2.