follow the installation steps and then :
- Start with your spotify credentials from terminal
librespot -u email@example.com -p yourpassword -n name_of_the_device
then on your phone/latpot on the same network you will get the raspberry as a device to play your music to .
Useful for home or to put your playlists before/after the concert etc
There are more recent forks in that I did not try yet , but this one just works