Now units can be assigned to metrics to help make sense of the data you're seeing. For example, you can specify that the data is measured in milliseconds, or that it measures bytes.
The drop down menu allows you to add new types of units to the list, and the default options include:
These unit labels will show up in graphs for those metrics. If all of the datapoints on a Y axis are using the same units, then the unit label will appear in the upper left corner of the graph next to the Y axis for easy reference.