This NIP is not yet in main. Here is an overview of PRs referencing this NIP. 
custom emojis in reactions MERGED @ZigBalthazar
NIP-30: add supported kinds MERGED @AsaiToshiya
Remove all NIP authors MERGED @fiatjaf
NIP-30: clarify the character set allowed in emoji shortcodes MERGED @jiftechnify
NIP-30: Custom Emoji MERGED @alexgleason
NIP-30 Resources CLOSED @plantimals