CURLOPT_TCP_KEEPINTVL(3) on macOS
The text b4f2f18c641e, 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 shipped it. The page shows this text now.
TCP keep-alive interval