macOS Catalina asks to introduce the new features. I agree. It opens Safari instead of Firefox, my default browser. Upon closing Safari, macOS asks if I want to keep Firefox as my default browser with the option to switch to Safari being in the default button position. Gross.
@jeremiahlee This was introduced back in Yosemite. Certain OS settings, such as the default browser setting, are protected from change and trigger a confirmation dialog. There has been a long history of default-browser setting hijacking attacks over the years, and the confirmation dialog is put in place to protect against that. The “Use ‘Safari’” button will show the name of whatever is your current default browser. Windows has the same sort of thing. https://www.ctrl.blog/entry/osx-protect-default-browser.html