fallback to get information from official youtube rss when API key is not configured

[write3371]

What feature is it?

fallback to get information from official youtube rss when API key is not configured

What problem does this feature solve?

format youtube rss so that it works in most of the rss readers

Additional description

No response

This is not a duplicated feature request or new RSS proposal

• [X] I have searched existing issues to ensure this feature has not already been requested and this is not a new RSS proposal.