The lcAsset element was deprecated in DITA version 1.3. It was replaced with the lcAsset2 element. It was originally intended to provide the images or other graphic assets to support the interaction.
+ topic/p learningInteractionBase-d/p learning-d/lcAsset
. . . <lcAsset> <image href="sunrise.gif"> <alt>the sun rising on Earth</alt> </image> </lcAsset> . . .