[userbinator]

Notepad is literally a window with the standard Windows Edit control inside it, so they certainly have the source code.

My guess as to why they don't care to support \n-only is that there's been very little need to; anyone who needs more advanced editing isn't going to use Notepad anyway.

As the sibling comment mentions, WordPad (which is similar but with a RichEdit control) does support \n-only.

[TazeTSchnitzel]

If you want notepad-with-LF-support, ReactOS, the open-source Windows NT clone, has this.