“Expected” metrics are a popular way of understanding how a team’s under-the-hood numbers might probabilistically manifest as more conventional metrics. That is to say it uses the NHL’s play by play, which captures information about shot type, distance, and angle, among other variables, to add a little more depth to pure volume based metrics, like Corsi. You can read more about it here, if you’re into that sort of thing.
The defending Stanley Cup Champion Washington Capitals are currently 6th worst in the League as measured by their expected goal share, registering a 46.