Similarly to PKT, where -SBJ function tag denotes a subject node, KTB offers three morpheme tags for the same purpose: jcs, jcc, and jxt.
while jcs and jcc roughly correspond to nsubj and csubj, jxt suggests that the phrase is the topic of the phrase or clause, but offers nothing informative in distinguishing whether it is in fact a subject (which it frequently is) and, if so, whether it is a clausal or nominative subject.