Due to how #2570 is needed for Mapdata, and main diverging greatly in #2753, I've decided to not add the feature back in the mapdata PR. There is no "correct" way to do it, as the additional text PR works on MarkerModel, which is basically getting deprecated and removed with mapdata. The most correct way to resolve this would be adding a secondary label attribute, supporting newlines in labels (if we don't already). We may also consider adding label rendering options, so users can decide whether a label is rendered above or below an icon.