The file specifies a set of measurement names and units. It is used to indicate the set of expected measurements that should be returned by a benchmark, as well as to indicate the units for each measurement name.
The file is specified in "split-out" format, using nested json structures to indicate a measurement's test_set name, test_case name, and measurement_name.
Here is an example from Benchmark.cyclictest. In this example, the fully qualified measurement names in tguid form would be:
For each of these, the 'units' for the measurement are indicated. In this particular case, the units are micro-seconds (abbreviated to 'us').
This file is read by the Fuego results parser to provide the units for each measurement, so they can be displayed in results visualization output.