It seems it’s hard to find the documentation for how you define smart playlists in Firefly Media Server (previously mt-daapd). I found them here.
Name (required)
Mail (will not be published) (required)
Website
This blog aims to deliver bite sized chunks of nothingness. If you find something of use then please take it with you and let it help you. If not, then come back later ... or don't, it's up to you.