Your point about Win10 EOL is interesting. I was aware of it; I don't really like what I see in demos of Win11; I'm putting off a decision about that; but that's a rant for another day.

I used to run Mac OS X (which became macOS) for quite a few years. The font it used for emoji was "Apple Color Emoji". In general, I liked the images used for the glyphs. Some seemed a little too detailed for viewing in a normal sized paragraph font; but in the main they were OK.

About 4-5 years ago, I switched to Win10. The font it uses for emoji is "Segoe UI Emoji". Its emoji glyphs were a little less detailed which was good; however, it chose to surround each with a thick, black border which I really didn't like (but put up with it).

I don't know exactly, but the release of Win11 was about the time of Unicode 10 or 11 (I'm guessing here). Unless "Segoe UI Emoji" completely stagnated, I received no further updates for that font. What I have been seeing for newer emoji glyphs is that the thick, black border had disappeared.

This current subthread prompted me to investigate a bit further. What I found was that my browser (Firefox) had been picking up the slack and rendering these newer emoji in its own font, "Twemoji Mozilla".

I keep a number of local HTML pages with notes for myself: TODO lists, HOWTO info, and such like. Just to liven these up a little, over time I've added emoji to the titles (and a few other places); for example, a page with skeleton code has a U+2620 SKULL AND CROSSBONES.

So today, I tweaked the CSS for those pages, putting "Twemoji Mozilla" before "Segoe UI Emoji", and pretty much all of those thick, black borders have disappeared. Yay!

It makes me wonder if Microsoft is not updating "Segoe UI Emoji" for Win10, but is doing it for Win11. Perhaps hoping for: "The new emoji are not rendering on my Win10, but look great on my friend's Win11: I should upgrade now!" — just a thought.