In Inkscape, transformation has a rather narrow meaning. Despite what the word might imply, it does not refer to any change of an object, but only to four simple operations that affect the entire object in the same way: moving, scaling, rotating, and skewing. Anything else is not transformation.
Metaphorically, transforming objects is simply moving around the furniture in your house without repainting the walls or opening up any cabinets.
Transformations applied to an object are often (but not always) stored as the transform attribute in SVG; for more on when it is or is not written, as well as the relevant preferences settings, see A.7 Transformations.