Emerald Theme Manager question

The Emerald Theme Manager with Compiz is working great in Ubuntu Mate 19.04 but

mate-terminal indicates this:

Warning: mailcap line not starting with a media type in emerald
Problematic line: application/x-emerald-theme; nametemplate=%s.emerald

How can I hide/or fix that?


Can you try another theme and see if you get the same error? But this may help with a solution: