This is superb! I have a small tool with a web frontend, that I use a specific emoji to represent but I didn’t have a favicon yet, because if I used a PNG of an emoji that Apple made I’d be infringing on their copyright.
Using SVG and having the browser and OS provide the rendering of the emoji is perfect for the favicon of my tool!
A quick search says it's possible to get the PNG data URL from a canvas. I wonder if it's viable to draw an emoji to a canvas, and extract the PNG out of it for the favicon.
Would a lawyer go after "client-side copyright infringement"?
Emoji, anywhere with text. If you mean favicon, you can see them in different places, but one example is top left of the tabs if you are using the device in landscape. If you mean desktop Safari then I don't remember as I don't use it on desktop.
OTOH if you want a quick favicon that renders consistently everywhere, Googles emoji set is available as SVGs (and fallback PNGs for Safari) under a permissive license.
I used this trick for a quick favicon on my site https://muxup.com/ - though unfortunately Google/Bing/DuckDuckGo doesn't like svg favicons and so it's not displayed in search results. I should really add a proper favicon...
Favicons have always been weirdly special. I don’t know why.
SVG support feels like it should be pretty straightforward to implement.
Last time I looked at how to implement favicons “correctly” I had to make some weird XML file with the word apple in it and it lists all the size of icons I have, and then use a favicon generator to create all the “correct” sizes.
This site has a nice one-click copy button for each "emojicon": https://emojicon.dev/