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iconfonts and unicode icons are two different things. unicode icons are the built in icons that renders correctly (but with slight variations) on any modern device, iconfonts are basically your own icons set as a font, hopefully using Private Use Areas for the codepoints.
> on any modern device This qualifier is why Unicode icons should be avoided where possible. You're correct that Unicode icons are different from icon fonts in the sense that they're standardized -- but the standard doesn't matter unless everyone implements it; and as we can see on HN, plenty of platforms don't. In practice, there are just too many platforms/devices that implement only part of the Unicode standard, o…
In practice unicode icons are widely supported enough to use.