How can I see which filetypes a given application can open? I have an app, it's refusing to open a file with a certain file extension. How do I check which file extensions it will open?
I think the go-to app is still RCDefaultApp (freeware). Hasn't been updated since 2009... still works in Mojave.

It can list &amp; optionally reassign any app, UTI, extension etc.