This filter is applied to use the addon category of child addon, it is including one parameter.
$addon_category_args -> is an array containing addons category.
An example of how you can append is below:
function add__addon_category( $addon_category_args ) { $addon_category_args = //passes arguments on this array. return $addon_category_args; } add_filter( 'rp_addon_category', 'add__addon_category', 10, 1 );