Maybe other monks have current data, but I recall times where Windows editors like Notepad and Notepad++ saved "Unicode" files under UTF-16-BE

While I'm pretty sure that's accurate for older versions of notepad.exe (it matches my memory; though as of current Win10 1903, even that shows choices for the encoding, including UTF-8 and UTF-16 BE/LE), that's not correct for Notepad++. In modern Notepad++ (v7.7.1), and as far back as I could try* (v4.0 from Jan 2007), Notepad++ has listed separate encodings for UTF-8, UCS-2 LE, and UCS-2 BE, not calling any of them the generic "Unicode" name.

(*: I tried most major versions backwards in time, and all agreed in the results. When I tried v3.0 from 2005, it wouldn't even run on my machine, so I didn't go any farther back than that.)