Synced lyrics and a system tray.
Lyrics: open the panel with the microphone button in the player bar. It follows the song line by line, highlights the current line, scrolls itself, and you can click any line to jump there. Lyrics come from LRCLIB first, then YouTube Music's own timed lyrics, falling back to plain text when nobody has a synced version. Matching is keyed on the track's exact length, so you don't get lyrics timed against a different cut of the song. Everything is cached locally, so replaying a track is instant.
Tray: closing the window now keeps the music playing and tucks Limusic into the system tray, with play/pause and skip controls in its menu. There's a switch in Settings if you'd rather have the close button quit, and an optional start-on-login toggle.