Instead of showing no legend for these layers, QGIS will now show the color ramp as a gradient bar.
Users can control the text for the min/ max labels, the direction of the bar, and the font settings.
This update also introduced changes to the internal API for vector renderers so that renderers have the flexibility to create other types of legend nodes other than QgsSymbolLegendNodes and provides the opportunity for future extensions to existing renderers.