User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:63.0) Gecko/20100101 Firefox/63.0 Steps to reproduce: Firefox had been pioneer on supporting different Emoji standard (CBDT/SBIX/SVG/COLR) standard. Now that harfbuzz provides a simple and safe API for color Emojis https://github.com/harfbuzz/harfbuzz/blob/master/src/hb-ot-color.h#L46 it would be nice if Mozilla could use it in order to simplify text rendering stack also, it avoids also having platform specific support like this https://github.com/mozilla/gecko-dev/blob/e75ab0ac9a9bf68d40ebcb002cb33de8398b8669/gfx/thebes/gfxTextRun.cpp#L541-L545 see https://github.com/harfbuzz/harfbuzz/blob/master/src/test-ot-color.cc as an sample code.