Where do I know, in which playlist a song from my library belongs....

[claus17]

...without checking each playlist for this song?

Thx for answering,

Claus

[Peter__]

Hey!

Welcome to the community 🙂

I don't think the Spotify client has this functionality, although feel free to correct me if I'm wrong. 

If you want to suggest it as a new feature, you can do so in the Ideas Section.

Peter