Notepad is, in fact, under active development. They recently upgraded find and replace so it works 90% of the time instead of 30% and added some annoying restore session by default feature. not to mention tabs

it will deprecate WordPad with a future Windows update as it’s no longer under active development

It doesn't need "active development" because it is perfect the way it is. Unix/Linux has tons of useful programs that haven't been in active development for 40-50 years.

Notepad is just a barebones text editor. I doubt there were any substantial changes since Windows 95, other than ensuring it runs on a 32 and later 64 bit infrastructure, and the menu works with newer releases. That sounds like a 1h per quarter job at most.

I haven't been using Wordpad for 20+ years. Notepad could do everything it does already. Then, you also have Firefox's built-in inspect to tinker with code on the fly.