All lyric text in a system sits on one shared horizontal baseline per verse row

Every syllable in a given verse row aligns to the same baseline across the whole system, regardless of the notehead's staff position.

Lyric text y-position is computed relative to each note's individual y rather than relative to a fixed staff-system baseline, so text visibly staircases up and down following the melodic contour.

Gould; Read (lyrics should be aligned along a common base line).

This rule is about where marks land on the page, so it can only be judged after engraving. Collision and spacing faults live here.