Horde3D

Do animation keyframes in the .anim files also contain scale?

If you have animation exported for character, and then scale the character model in the 3d-modeling tool and export the character mesh again,
animation playback will rescale model to scale old character was exported on, and sx/sy/sz values in the new model.scene.xml doesn't have any effect either, which is very annoying...

Yes, the animations do contain scale. The behavior you describe is desired. If you want to scale the whole model, apply a transformation to the model node.