// map(programID -> File)
static Map<S, File> gazelle_loadConceptFilesFromCentralMachine() {
  new Map<S, File> files;
  S computerID = gazelle_centralComputerID();
  for (S programID : gazelle_dataProgramIDs())
    files.put(fsI(programID), dm_retrieveFileFromOtherMachineIfDifferent(computerID,
      "JavaX-Data/" + fsI(programID) + "/" + conceptsFileName()));
  ret files;
}