Emotion adds a css property called label, the value of it is appended to the end of the class name, so it’s more readable than a hash. babel-plugin-emotion adds these labels automatically based on the variable name and other information, so they don’t need to be manually specified.

/** @jsx jsx */
import { css, jsx } from '@emotion/core'

let style = css`
  color: hotpink;
  label: some-name;

let anotherStyle = css({
  color: 'lightgreen',
  label: 'another-name'

let ShowClassName = ({ className }) => (
  <div className={className}>{className}</div>

    <ShowClassName css={style} />
    <ShowClassName css={anotherStyle} />