The Safari Technology Preview update includes 186 fixes and updates to HTML JavaScript, display, web animation, and Web API, and the current Safari Technology Preview release is compatible with devices running macOS Ventura and macOS Sonoma, the latest version of macOS that Apple launched in September 2023.
The Safari Technology Preview update is available through the software update mechanism to anyone who has downloaded the browser, and the full release notes for the update are available on the Safari Technology Preview website.
Apple's goal of Safari Technology Preview is to collect feedback from developers and users about the browser development process. Safari Technology Preview can run alongside the current Safari browser, and although it is designed for developers, it does not require a developer account to download.