When no user is logged in, clicking the YIM 2021 navbar link on mobile directs the user to the broken link:
https://listenbrainz.org/user//year-in-music

Instead of:
https://listenbrainz.org/user/<user>/year-in-music

The jinja template for the navbar needs to ascertain whether a user is logged in, and hide the year in music link if not.