This report, according to the Google help document, provides three new metrics: (1) relative visibility, (2) page overlap rate, and (3) higher position rate.
#Relative visibility indicates how frequently your competitors' offers are displayed in comparison to your own. In other words, this is the number of displayed impressions from a competitor shop divided by the number of displayed impressions from you for a given product category and country over a given time period.
#Page overlap rate: The frequency with which competing shops' offers are displayed alongside your offers on the same page is referred to as the page overlap rate. In other words, this represents the ratio of the number of times you and a rival merchant obtained an impression for at least one shown offer divided by the number of times you received an impression for at least one offer.
#Higher position rate: The higher position rate indicates how often a competitor's offer was put above yours on the page. To put it another way, the number of times a competing merchant received an impression for at least one product in a higher position on the page than you, divided by the number of times you and a merchant appeared on the same page together.