Since the introduction of the ‘fmp’ uri scheme, RCDefaultApp preference pane has been a go-to solution for Mac users. The venerable utility was “developed way back when by Carl Lindberg,” as cited by the author of SwiftDefaultApps. In
RCDefaultApp had been limping along if you could find a trustworthy copy, even working for me in earlier versions of Catalina. However, today, after installing 10.15.5, it simply wouldn’t run. With a little searching, I found this open-source replacement project. In the author’s own words:
“This Preference pane is chiefly intended to be a modern replacement for the amazing RCDefaultApp developed way back when by Carl Lindberg.”
You can download the latest release from the GitHub project.