Some Unicode miscellaneous symbols and pictographs exist in two variations: a text style and an emoji style. The two are distinguished by the presence of U+FE0E VARIATION SELECTOR-15 for text style and U+FE0F VARIATION SELECTOR-16 for emoji style (it's not clear to me which is the “default” or whether this even means anything).
For example, ☠︎ (U+2620 SKULL AND CROSSBONES followed by U+FE0E VARIATION SELECTOR-15) is a text style “skull and crossbones” whereas ☠️ (U+2620 SKULL AND CROSSBONES followed by U+FE0F VARIATION SELECTOR-16) is the corresponding emoji.
(Typically, the emoji style will display in color whereas the text style will display in black and white, but I'm not sure this i

