src/elements/Placeholder/Placeholder.js
function Placeholder(props) {
  const { children, className, content, fluid, inverted } = props
  const classes = cx(
    'ui',
    useKeyOnly(fluid, 'fluid'),
    useKeyOnly(inverted, 'inverted'),
    'placeholder',
    className,
  )
  const rest = getUnhandledProps(Placeholder, props)
  const ElementType = getElementType(Placeholder, props)

  return (
    <ElementType {...rest} className={classes}>
      {childrenUtils.isNil(children) ? content : children}
    </ElementType>
  )
}
function Placeholder(props) {
  const { children, className, content, fluid, inverted } = props
  const classes = cx(
    'ui',
    useKeyOnly(fluid, 'fluid'),
    useKeyOnly(inverted, 'inverted'),
    'placeholder',
    className,
  )
  const rest = getUnhandledProps(Placeholder, props)
  const ElementType = getElementType(Placeholder, props)

  return (
    <ElementType {...rest} className={classes}>
      {childrenUtils.isNil(children) ? content : children}
    </ElementType>
  )
}
A placeholder is used to reserve splace for content that soon will appear in a layout.