Currently FrameNet does not contain frames that would be appropriate for the expression "Bruch vollzogen" and the word "Vorgänger" of this sentence. So both words have been assigned an "Unknown" frame. Still the core frame elements present have been marked as Fe1 and Fe2.
The first "Unknown" frame is being evoked by the words "Bruch vollzogen". As there is no single node of the syntactic structure that covers these words, the edge for the frame-evoking element is split.