Projecta: Entries -

Saving a set of selected features from a large layer is now much faster
Updating only selected features using the field calculator is faster
Faster zoom to selected on large layers
Much faster get_feature expression function (especially when the an indexed column in the referenced layer is used)
SelectByAttribute and ExtractByAttribute processing algorithms are orders of magnitude faster, and can take advantage of database indices created on an attribute
PointsInPolygon processing algorithm is many magnitudes faster
Filtering the categories in a categorised renderer (eg, only showing some categories and unchecking others) is much faster, as now only the matching features are fetched from the data provider
Significant reduction in the memory required for opening large vector layers