subj relation is used for all subjects, regardless of their form (nominal or verbal). This relationship encompasses both the
csubj relationships as defined by UD, as the following examples show.
Deep syntactic features
subj relation has two deep syntactic sub-relations. The sub-relation
subj@expl is used to indicate that the subject is present to fill in an obligatory syntactic position and has no semantic value. You can find more information about the expletive constructions on this page.
Meanwhile, the sub-relation
subj@pass is used to indicate a passive construction. This sub-relation can be used for both standard passive constructions, and for mediopassive constructions.
You can find more information about passive constructions on this page.