yes, microsoft does hold a trademark for notepad. As litigious as MS is I'm pleasantly surprised they've left notepad++ alone.
Unfortunately anthropic is actively eroding community goodwill in regards to potential IP conflicts:
https://abnormal.ai/blog/abnormal-response-to-anthropic-laws...
Microsoft has a lot of trademark meant to protect them from agression rather than attack themselves
If MS can go after notepad++ then Bjarne Stroustrup can go after C#?
I made "qNotepad" in college, it's been on GitHub forever, never gotten any DMCAs or anything. Maybe they don't care that deeply?