Safari Technology Preview release 5 includes a bug fixes and updates for JavaScript, CSS, web APIs, Web Inspector, media, security, networking, and accessibility.
The Safari Technology Preview update is available through the Mac App Store to anyone who has downloaded the browser. Full release notes are available on Apple's Safari Technology Preview website.
Apple's goal with Safari Technology Preview is to gather feedback from developers and users on its browser development process. Safari Technology Preview can be run side-by-side with the existing Safari browser and while aimed at developers, it does not require a developer account to download.
Article Link: Apple Releases Safari Technology Preview 5 With Bug Fixes and Feature Tweaks