Filegraph is a graph of files in a git repository, where a node is a file and a weight from 0.0 to 1.0 of edge (A, B) represents how much file B is relevant to file A. The tool has subcommands to compute relevance between any two files based on the shortest path, where distance is -log(relevance), as well as order files by distance from a given set of root files. This can be used to order tests by relevance to files modified in a CL.
TODO(nodir): elaborate.