Is Safari's "Close Tabs to the Right" a new feature released in macOS 10.15.4? After updating to macOS Catalina 10.15.4, I've noticed a new Close Tabs to the Right option when right clicking a Safari tab:



I'm not 100% sure if this came with the 10.15.4 update thought, since the release notes don't actually say anything about this. When did this feature first appear?
It's new in Safari 13.1, even on Mojave.
Safari 13.1 will run on macOS High Sierra, Mojave, and Catalina (specifically versions 10.13.6, 10.14.6, and 10.15.4), It's the Safari version that's key, not the OS version itself.
Here's the changelog which show this: Safari 13.1 Beta Release Notes


Added Close Tabs to the Right.

Added Duplicate Tab.