c_gtk_tree_drag_dest_row_drop_possible

Undocumented in source but is binding to C. You might be able to learn more by searching the web for its name.
__gshared extern (C)
int function(GtkTreeDragDest* dragDest, GtkTreePath* destPath, GValue* value) c_gtk_tree_drag_dest_row_drop_possible;

Meta