تَابِعٌ: it follows an antecedent in case.
غَيْرُ صِفَةٍ: it is not an adjectival description.
يُوَضِّحُ مَتْبُوعَهُ: it identifies the preceding referent.
أَشْهَرُ اسْمَيِ شَيْءٍ: the author characterizes it through a clearer name for the same entity.
The key function is clarification of identity.