The lcMatchingItem element was deprecated in DITA version 1.3. It was replaced with the lcMatchingItem2 element. It was originally intended to provide the content for the matching side of a matching pair of items in a match table interaction.
+ topic/stentry learningInteractionBase-d/stentry learning-d/lcMatchingItem
... <lcMatchingPair> <lcItem>Boston</lcItem> <lcMatchingItem>Red Sox</lcMatchingItem> </lcMatchingPair> ...