Derived
The DERIVED_FROM edge from a proposition to a shared SourceNode. The per-proposition span (chunkId, offsets, the entry's own content hash) rides on the relationship; the source itself is the shared node. Together they reconstitute a dice ProvenanceEntry.
sourceRevision rides here too, for the same reason the span does: which version of a source a claim was read from is a fact about this citation, and the :Source node stays shared across every revision of it.
entryKey is the edge's own identity: the string ProvenanceEvidenceKey mints for the entry, the same one a collapse records when it folds that evidence away. The relationship needs an identity because a proposition can cite one source at several revisions, and an edge identified only by its two endpoints would collapse those into a single row. Writes MERGE on it. Edges written before revisions existed have no entryKey; they are adopted on first touch by an exactly matching revisionless entry.
display is the label the writer of this citation supplied. The shared :Source node only keeps the first writer's label, so a read prefers the edge's own display and falls back to the node's for edges written before this field existed.