zshcalsys(1) on macOS
The text 16da510591e6, as macOS 26.5, macOS 26.4, macOS 26.3, macOS 26.2, macOS 26.1, macOS 26.0, macOS 15.6, macOS 15.5, macOS 15.4, macOS 15.3, macOS 15.2, macOS 15.1, macOS 15.0, macOS 14.6, macOS 14.5, macOS 14.4, macOS 14.3, macOS 14.2, macOS 14.1, macOS 14.0, macOS 13.5, macOS 13.4, macOS 13.3 shipped it. The page shows this text now.
zsh calendar system