Kdenlive/Manual/Effects/Crop and transform/Scale and Tilt
Scale and Tilt (ver <=0.9.2) or Crop, Scale and Position (ver >=0.9.3)
This is the Frei0r scale0tilt MLT filter from Richard Spindler.
In version 0.9.3 it was renamed from Scale and Tilt to Crop, Scale and Position
Scales, Tilts and Crops an Image
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See also Pan and Zoom which can do very similar things and may do them better.