But I would say, continuous refactoring is maintenance. You would not need to do it unless there was technical debt that had not been addressed in a timely mann

But I would say, continuous refactoring is maintenance. You would not need to do it unless there was technical debt that had not been addressed in a timely manner. And when you are forced to do development because your underlying platform, i.e. javascript, changes, that's maintenance. You're not adding anything, you're just adapting. Though I concede that to the extent that the JS changes allow new capabilities and you engineer them in, that's a gray area.