Glissando lines are reflected in playback using a sequence of notes, all a small interval apart, between the start and end notes for each glissando.
Glissandos belonging to harps consider the current harp pedaling when determining the pitches to use in playback. Glissandos for all other instruments use the 12-EDO chromatic scale, regardless of the current tonality system.
When glissando lines start or end on tie chains, their playback starts on the last note in tie chains and ends on the first note in tie chains.
By default in playback, glissandos sound across their full duration, but you can delay the start of glissandos in playback individually.
Playing back glissando lines as a continuous, smooth slide is not yet supported. This is planned for future versions.