Groups edges by the consuming file each originates from -- the inverse
of groupEdgesByCapability. Only files with at least one edge appear,
sorted by file. Takes edges alone: unlike a capability, a file is only
ever known to this projection because it produced at least one edge.
Groups
edgesby the consuming file each originates from -- the inverse ofgroupEdgesByCapability. Only files with at least one edge appear, sorted by file. Takesedgesalone: unlike a capability, a file is only ever known to this projection because it produced at least one edge.