He might not have a Mac to test it on or care to code it. It’s open source, they work on what they want after all they don’t get paid. If he was donated a Mac and enough money in sure he might look into it
If you want an editor with the same core as Notepad++, but fewer batteries included and more extensibility, Textadept is worth a look.
When there are no trademark issues then there are no trademark issues to discuss.
But they haven't named it something else, so here we are talking about the trademark issues that this raises.