Location in wpsl_store_header_template filter

The wpsl_store_header_template function depends on being passed a $location parameter. If we filter the output of this function, we don’t currently have access to that parameter. The apply_filters call can accept extra params, so could be updated (underscore-functions.php, line 227):

return apply_filters( 'wpsl_store_header_template', $header_template, $location );