"_" is when you must assign a value, but don't want to use it.

range in the for loop return 2 values (index, value). If you don't want the index, you can assign it to "_" to ignore it.

http://golang.org/ref/spec#Blank_identifier

It's the "blank identifier", a throw-away variable. See http://golang.org/ref/spec#Blank_identifier

For iterates over a range and returns the index and the value. If you don't use the index the underscore just ignores it.

AFAIK the function returns to values but you only need name in this case, so _ discards that return value.