Empty table-row baseline

[gsnedders]

css-align-3 says:

If any cells in the row participate in first baseline/last baseline alignment along the inline axis, the first/last baseline set of the row is generated from their shared alignment baseline and the row’s first available font, after alignment has been performed. Otherwise, the first/last baseline set of the row is synthesized from the lowest and highest content edges of the cells in the row. [CSS2]

Notably, this doesn't cover the case when there are no cells in the row (i.e., the row is empty and has no descendants).