_WP_Dependency is a class defined in
wp-includes/class.wp-dependencies.php that holds information about an items in a
WP_Dependencies queue. This class is internal to
There are two different properties that hold additional information for an item: $args and $extra. The former is a scalar that holds registration data (data provided when the item was added to the dependency queue). For example, $args for
WP_Styles holds the stylesheet media, whereas for
WP_Scripts, it's a dependency group. $extra is an array that holds arbitrary data added via
add_data(). For example, it can hold the title of a stylesheet or raw style rules.
_WP_Dependency is located in