ODF 1.2 Part 1 cd03 contains clarified wording regarding the interpretation of matrix elements for dr3d:transform. Unfortunately inconsistent with other relevant standards (like svg or pdf), row-major order was chosen:

"The values describe a standard 4x3 homogeneous transformation matrix, where the right column (<d>, <h>, <l>) describes the translation."

(c.f. e.g. http://www.w3.org/TR/SVG/coords.html#TransformMatrixDefined). To make matters worse, to date all major implementers seem to interprete the matrix attribute the svg way.