One key reason managing Adwords campaigns can be difficult is match types. Aside from search query reports, Google provides extremely limited visibility of what really happens with match types.
A new segment now available in Adwords at the keyword level is search term match type. It can be found under the segments menu (as shown above) and the screenshot demonstrates what this metric displays.
It shows the number of impressions and other metrics each keyword drives across all match types. It is completely irrelevant for exact match but for phrase match it displays how many times your keyword has displayed in exact or phrase match situations, and for broad match, metrics when the keyword exact or phrase matched the search query.
Thus it can show where you have missed a negative exact match on a broad keyword or where a broad keyword might be more efficient on exact or phrase match. Google is allowing advertisers to make more effective match type decisions and ultimately providing more visibility in a key area where advertisers have long been asking for more clarity.
However if you are running campaigns which carefully follow Google best practice, such as exact match in the majority and negativing all exact matched terms on the other match types, then this will show no data under alternative match types and thereby be of no use.
New accounts which heavily rely on broad match will benefit on the info but long running and week optimized accounts will not.
Finally, broad match modifier is not separated out and so I imagine this is included in broad match figures.