The drink is basically what would be a plain Macchiato at most other coffee shops/cafes (macchiato is Italian for "marked").
The name is a bit confusing at Starbucks because they already offer a Caramel Macchiato and the two similarly named drinks fall on opposite ends of the spectrum as one (the Caramel Macchiato) is more of a dessert-type drink, while the other offers a stronger coffee profile than the rest of Starbucks' espresso and milk drinks.
Starbucks' Latte Macchiato features foamed whole milk marked by two espresso shots.
In terms of the strength of the coffee flavor, the drink is slightly more "coffee-forward" than the recently introduced Flat White (which, at Starbucks, is also technically a "marked" drink [with a milky dot] but not a "macchiato" on the Starbucks menu) but less so than an Americano. You can see where it falls in the range here:
The new drink can be found at Starbucks locations in the U.S., Canada, and most of Latin America.