Kdenlive/Manual/Effects/Crop and transform/Scale and Tilt
Crop, Scale and Tilt
This effect was previously named as Scale and Tilt and Crop, Scale and Position
This is the Frei0r scale0tilt MLT filter from Richard Spindler.
Scales, Tilts and Crops an Image
See also Pan and Zoom which can do very similar things and may do them better.