Apple has released its Big Sur and Catalina Safari 15.1 beta version to developers for testing and troubleshooting purposes. The 15.1 version is also available in beta for macOS Monterey users.
The recent beta release features a notable change, particularly a reassigned Favorites bar. It’s been moved to the tab bar where it was originally before Safari 15 was released. In the Monterey release Safari’s look has been changed, with a new tab design that proved to be unpopular. Apple has been refining the browser’s design since then.

Developers can check out the Safari 15.1 beta software by signing in to the Apple Developer website then going to the ‘More Downloads’ section. After downloading the software, developers will need to have the latest beta version of macOS Catalina or macOS Big Sur to successfully install 15.1.
Full patch and support notes are available to view on Apple’s official website.