Why copying a transform to txt get a 4d rotation “XYZW”?

92045-report.png

When I copied this transform array to a txt file, I got the following data:

((Rotation=(X=-0.038135,Y=-0.189308,Z=0.239298,W=0.951549),Translation=(X=1.000000,Y=0.000000,Z=0.000000),Scale3D=(X=1.000000,Y=1.000000,Z=3.000000)),(Rotation=(X=-0.069881,Y=-0.498913,Z=0.300647,W=0.809823),Translation=(X=0.000000,Y=2.000000,Z=0.000000),Scale3D=(X=1.000000,Y=2.000000,Z=1.000000)))

While the Location and Scale data got right, the Rotation data were transformed to a 4d vector of XYZW.
I wonder how to get the transformation formula?