If you are working with tiles, you can't use these glyphs because you can't specify the tile font and PUA glyphs are not available via font-fallback. Use these glyphs only when you can explicitly specify the Segoe MDL2 Assets font. Only use these glyphs when you can specify the Segoe MDL2 Assets font. If the font is not available, the glyphs won’t show up. This is useful when creating a symbol font, but it creates an interoperability problem. The PUA allows font developers to assign private Unicode values to glyphs that don’t map to existing code points.
Most of the icons and UI controls included in the Segoe MDL2 Assets font are mapped to the Private Use Area of Unicode (PUA).
Segoe UI Symbol will still be available as a 'legacy' resource, but we recommend updating your app to use the new Segoe MDL2 Assets. With the release of Windows 10, the Segoe MDL2 Assets font replaced the Windows 8/8.1 Segoe UI Symbol icon font.
