Access to the file was denied on macOS
When I try to open a local file using file:///Users/myuser/Documents/... , I get "Access to the file was denied". I'm on macOS 10.15.5. GetInfo on the file shows that I have read and write access. Firefox version is 77.0.1. I can't recall whether I gave Firefox permission to access my Documents folder when I first ran it on macOS 10.15. If I didn't, I don't know how to now give it access.